Interesting that no one has responded to your post, Redheart.
The rifle you are asking about is now in the Museum of the Fur Trade collection. I saw it on exhibit when I last visited the museum about 18 months ago. It is pictured on page 388 in FIREARMS OF THE FUR TRADE by James A. Hanson.
The best pictures of the rifle can be found in James D. Gordon's GREAT GUN MAKERS OF THE EARLY WEST Vol III on page 385. Here you will be able to see many of the details of the rifle, though Gordon doesn't list any of the dimensions of any of the rifles in his three-volume set other than occasionally giving the caliber of a gun.
Here are a few pictures of the rifle to get you started.
Some of the original color case hardening can still be seen on the breech plug.
As seen it the picture of the forearm, the barrel wedge escutcheons have a fatter oval shape than later S Hawken rifles.
The finial on the toe plate is different than the traditional beaver tail finial.
If you wanted to try to duplicate this rifle, I would suggest using TOTW's butt plate #BP-Hawk-L-I.
For the trigger guard, I strongly recommend TOTW's #TG-Hawk-H-I.
I believe this trigger guards reflects Don Stith's influence on casting a proper S Hawken trigger guard. The one you commonly see on contemporary Hawken rifles has too much curl in the scroll at the end of the guard.
John Baird illustrated the proper shape of the scrolls found on many J&S and Sam Hawken rifles in his article in the May, 1967 issue of MUZZLE BLASTS. For some reason, he didn't include that chapter in his book where more would have seen it and may have paid more attention to the detail. In Baird’s words, "The scroll guards found on early J&S Hawken rifles all tend to form a complete circle...Later [Sam] Hawken guards tended to be with a tighter, more oval form of scroll, with the rear portion nearly forming a right angle to the bottom of the stock."
Baird's illustration of the different scrolls.
This original S Hawken rifle is a good example.
This picture of an original J&S Hawken illustrates the earlier version.
For the lock on the MFT rifle, you can use any of the T. Gibbon's style locks such as the Ron Long designed lock from R. E. Davis or L&R's Hawken lock. You will probably want to try to find one of L&R's old hammers or one of the old Cherry Corners Hawken hammers. The R. E. Davis hammer is too thick for this rifle (you may be able to file it to a more similar shape) and the current L&R hammer is unlike anything I've seen pictured on any original Hawken rifle.