Here are some pics, if that helps:
The lock, with the three switching buttons
Underside of lock (sorry, a little fuzzy.) It says “System F.W Heym M. Suhl”
What’s so strange about that? It looks to me, too, like a work of art more than a hunting piece.
If none of the other avenues mentioned work, you might try writing some of the rabid gun fan magazines. Works for a lot of different hobby-related items.
Try the Library reference desk. They usually have collector’s books on guns. If not they can get information from many other libraries.
Also if you want to e-mail me with all the details I can have my hubby look into it later this week. He has several gun value guides that are fairly up to date. Just be sure you use SDMB in the subject line as I don’t open anything not send by someone I know.