Hey there, I have an old black powder pistol that was my late father's that has no serial or manufacturer identification besides an 'X' on the underside of the barrel. I've taken it to a local gun shop whose owner was perplexed, as was an associate of his, and a few other gun enthusiasts I've asked; who can only tell me that it's definitely a black powder cap gun, but that's it. Some Reddit folks were very helpful, mentioning that it looks like a well-made, one-of-a-kind boutique or homemade gun. It weighs 1 lb 4 oz and measures approx 9 in length and 5 in height (top of sight). Attached are a few pictures. I have someone who'd like to purchase it but I have no idea of its value, or even if it still shoots -though the mechanisms seem to be in good working order. I appreciate anything you can tell me.