I read about something that looked just like that a few months ago. The are supposed to have a trigger that flip downs I think? It was developed by Henry M. Kolb & Charles Foehl in Philadelphia, PA during the years you where referencing. I think the article said in good condition they are worth like 500 bucks. I have no idea on where to get parts, but I know these shoot .22 short. I believe the article with in guns and ammo, I threw it away though after I read it. Maybe this helps..