M29since14:
I went back and reviewed more sources. There is a discrepancy in information related to the 4 1/2 inch engraved 44 Magnum.
The Gun Digest Book at this address:
The Gun Digest Book of the .44 - John Taffin - Google Books
clearly says that the 4 1/2 inch engraved revolver pictured was the first 44 Magnum Elmer received, and that it was cut down from 6 1/2 inches, engraved, etc., by The Gun Reblue Company, and that the cut back revolver was featured in the 1958 Gun Digest. See page 143.
However, the November 2008 issue of Handloader has an article by Brian Pearce about the Elmer Keith museum. Volume 43, No. 6 shows a picture of both the 6 1/2 inch 44 Magnum and the 4 1/2 inch engraved, cut-back, 44 Magnum. That article, by Brian Pearce, begins on page 256. The article says that S147220 was the third 44 Magnum shipped, that it was shipped to Elmer Keith and that it had a 6 1/2 inch barrel. The article goes on to state that the 6 1/2 inch is pictured (original barrel intact), and that it was the one Elmer used to make the finishing shot on the Mule Deer at +/- 600 yards. In that same article is a picture of the 4 1/2 inch cut back 44 Magnum, with the engraving and signature, and the ivory stocks. The plaque displayed with the 4 1/2 inch engraved revolver reads, "This original barrel length on this very early 44 Magnum was 6 1/2." Keith had Don Gowan of the Gun Reblue Co. cut the barrel to 4 1/2 inches, cover it with full engraving and stock it with ivory in Keith's favorite carving pattern, the Longhorn steer."
The Taffin article, however, seems to disagree with the Pearce article. Taffin states:
"Keith's first .44 Magnum was a 6 1/2" Smith and Wesson that was soon cut to 4 1/2", and engraved and stocked by the now defunct Gun Reblue Co. This sixgun was featured in the 1958 Gun Digest. It too is a beautiful specimen with its full engraving and steerhead grips and like all of the .44's, has Keith's signature on the sideplate." The Taffin article is here:
THE SIXGUNS OF ELMER KEITH
So, in conclusion, I have no idea. I always thought, based on the Taffin information and the information on the plaque with the display, that the 4 1/2 inch cut back from 6 1/2 inch was the first 44 Magnum Keith received. If I were betting, however, my bet goes with Taffin.
EDIT: See also here:
http://www.sixguns.com/BookOfThe44/bot44c21.htm
and check the caption under Picture 21-22.
I hope that helps.
Shawn