Sounds like it's a German gun. The Germans have this thing about screws and lock screws that line up, very intricate machining, and elaborate carving and engraving on many of their firearms. The Colorado gunsmith you speak of may have simply rebuilt the gun or restocked it. If he had actually built the gun, he would have had to mark it, and he would not have used German proofmarks.
Never try to educate someone who resists knowledge at all costs.
But what do I know?