Buchel Free Pistol with Tell barrel

I am trying to find information on a pistol which my grandfather purchased sometime between the 1930's and 1950's. It is a handmade Tell free pistol made by Buchel with a Widmer barrel. This is a falling block type, single shot pistol with an elaborate grip and dual trigger firing mechanism (I think all of that information is correct, I'm going from memory at this point. It may be a Tell barrel. Please pardon any errors).

Upon inheriting the pistol, my father did some research and found Several Articles written by Walter F Roper for Americal Rifleman between 1939 and 1941. These articles mention the pistol, but give little real information. He also found an article from "The Man's Magazine" from about 1952 which detailed free pistols and rifles in general, This article has a photograph of the pistol, but again, no information.

OK, that's what I don't know. Here's what I do. This is, to the best of my knowledge, the same model pistol which was used by Torsten Ullman of Sweeden to win the free pistol class of the 1936 olympics and set a world record score of 559/600 in the competition. The name Buchel is engraved on the release lever for the falling block action. The barrel has the number 1768, and the name Wycheur, along with a monogram, stamped on the bottom of the barrel, near the breech.

My father contacted a Specialist on antique firearms to try to get additional information on the pisotl, but unfortunately, the information which they provided was nearly a word for word rehash of the American Rifleman articles. I am trying to find any information or source of information on this pistol so that I can get an accurate insurance value for it. If anybody knows who I should talk to, or has any information regarding this pistol, I would love to hear from you.

Thank you
Scott