To sum up in a short chronology here what facts posters brought to this thread,
1-Sometime after Joseph Smith's death and 10/17/1855, the KEP were transported from Nauvoo to Salt Lake City, where on 10/17/1855 there is a catalog entry for them by the Church Historian, George A. Smith
2-The Church did not bring out the KEP despite the "violent" public attack on the BoAbr by Reverend Franklin S. Spalding in 1912-13.
3-Prior to 2/16/1935, Dr. Sidney B Sperry (BYU) and his student assistant, James R Clark, had inquired of the Assistant Church Historian and staff at that office about the KEP, but been told that it was perhaps lost in transport from Nauvoo
4-On 2/16/1935, the Des News published an article about the KEP and the fact it was kept in a box by the Church Historian
4-During the week of 2/18-22/1935, armed with the Des News article, Dr. Sperry and Clark met with Assistant Church Historian, A. William Lund, who within 15 minutes was able to produce the KEP box for Dr. Sperry and Clark
5-In 1935 and 1936, Dr. Sperry and Clark were allowed to work on the KEP, but not cleared to make any public anouncement
6-Dr. Sperry's contribution to the 1938-39 MIA manual included a lesson for 11/8/1938, described but it did not disclose that the Church had the KEP and misleading that he had not seen the KEP when in fact he had, by couching his descriptions in terms of "it seems quite probable that" and "we can readily imagine".
After having explained the purpose of the Grammar,
Dr. Sperry wrote:“It seems therefore quite probable that the alphabet was arranged very much as follows. On the extreme left of the page the signs in question would be written down in a vertical column. To the right of this column would appear the sounds of the Egyptian sign or hieroglyphic in English letters together with an interpretation of the character in questions. We can readily imagine that some grammatical phenomena of the language would be revealed in the notes which the Prophet wrote down. It would seem rational to suppose that after the Prophet had written down many pages of these signs with their meanings he would become more and more competent to read them as they appeared on the papyrus.”
7-onandagus recalled that the fact of the Church's possessing the KEP was made known publicly before 1966, but rather than by Walter Whipple's concordance which Amazon lists as having a print date of 1972 and is the now out of print
A concordance and dictionary to the Egyptian alphabet and grammar: In parallel with the Book of Abraham, by Walter L. Whipple
http://www.amazon.com/s/ref=ntt_athr_dp_sr_1?_encoding=UTF8&sort=relevancerank&search-alias=books&field-author=Walter%20L%20Whipple.), it was discussed in Clark, James R.
The Story of the Pearl of Great Price. Salt Lake City: Bookcraft, 1962.
8-Gerald and Sandra Tanner obtained a microfilm image of the KEP from James A. Wardle, and the Tanners went public with the images of the KEP in their 1966 book,
Joseph Smith's Egyptian Alphabet & Grammar, which appears to have been the first wide-spread availability/distribution for the public to see the KEP.
9-A large donation by a donor whose identity the Metropolitan Museum of New York has kept confidential resulted in that museum turning over the Joseph Smith papyri that it had purchased in 1947 and had since then been part of its collection
An interview in Dialogue: A Journal of Mormon Thought, Winter, 1968, pp. 55-64, with Dr. Henry G. Fischer, Curator of the Egyptian Collection at the Metropolitan Museum of Art--
DIALOGUE: Is this a standard practice to give such documents to interested private institutions such as the Church?
FISCHER: I am glad you asked that question, since, technically, we have not given the documents to the Church. As far as the Church is concerned, it is a gift, of course, but it was made possible by an anonymous donation which covered the cost to the Museum. We have not set a precedent for giving away an object; we cannot be in that position.
DIALOGUE: Would you say that the Church does not have complete ownership? Is there a way by which these documents could be called back?
FISCHER: No absolutely not. They are a gift from the Museum, but the gift was made possible because of an anonymous donation from a friend of ours.
10-That museum on 11/27/1967 publicly donated to the Church the found papyri. (Interestingly, University of Chicago Egyptologist Klaus Baer had alluded to this more than a year earlier in his 9/20/1966 letter to Grant S. Heward: a "lot of eleven papyri from the Joseph Smith collection that will probably make a reappearance in the not too distant future.")
11-The significance of how the KEP ties some of the text of the BoAbr to the found papyri (but the Egyptian characters on that papyri do not translate into anything close to the BoAbr text) was set forth by Grant S. Heward and Jerald Tanner in "The Source of the Book of Abraham Identified," Dialogue: A Journal of Mormon Thought 3.2 (Summer 1968) pp. 92-98.
12-In "Prolegomena to Any Study of the Book of Abraham",
BYU Studies, Vol. 8, No. 2, (1968) pp.171-190, Hugh Nibley wrote with a very defensive tone (emphasis added):
It was hidden and suppressed for the same reason that Brigham Young's laundry lists are hidden and suppressed, because it was nobody else's business. Let us allow Joseph Smith at least for the time being the luxury of a moment of privacy, of a little speculation on his own there on his hands and knees in the front room of the Mansion House, with papyri spread out around him on the floor. The fact that he kept his notes strictly to himself is evidence enough that they were his own private concern and were never meant as a message to the Church.
13-In 1971, Nibley pronounces the Grammar is "of no practical value whatever." Hugh Nibley, "The Meaning of the Kirtland Egyptian Papers," BYU Studies 11, no. 4 (Summer 1971): 357.
http://byustudies.byu.edu/PDFLibrary/11.4Nibley.pdf14-In 1981, Michael Marquardt made an improved compilation of the KEP available in his book,
The Joseph Smith Egyptian Papers.
15-A few years later, Steven F. Christensen was able to have hi-res photos taken, and from the negatives four sets of color prints were made, some of which are now in the possession of George D. Smith, Edward Ashment and Brent Metcalfe.
So, despite the naysaying TBMs in this thread, it does appear, as their beloved Nibley wrote, the Church hid and suppressed the KEP for sometime.
At least Nibley has postulated a reason why the Church hid and supressed the KEP. Do any of the TBMs now think the hiding and suppression was because even before the papyri was found in a New York museum and turned over to the Church, the Church knew the KEP was problematic for the Church's claims that the BoAbr is authentically what it purports to be and Joseph Smith said it was?
