Hello everyone, I am new to this forum and I have zero experience with Black Powder guns. I am helping a family member sell some of her deceased husbands guns and he had one black powder gun that I know zero about. I think it is a kit gun but I cant be sure. I have removed the barrel and there is no markings that I find useful. There is a serial number on the barrel, and the markings " for Black Powder only" and there is a small circle that is cut in half with a zig zag line ( see photo) with the words 50 Cal. Inside of the patch pocket on the butt stock there is the stamp of what appears to be AF and the number 6813pl engraved (see photo) The octagon barrel is 33 inches long and the over all length is 49.5 inches long. I have someone that wants to buy it but I have no idea what to ask for it. I have found kits for sale new from $400 to $1200. I want to make sure the widow gets what is a fair price for it without ripping the buyer off. Any help would be appreciated.