On Pawn Stars a gent brought in a Trapdoor Springfield line-throwing gun. He had some documentation on it, and it appeared to be legit (IIRC...I've only seen one). Cory aka "Big Hoss" says the gun would have been more valuable if it hadn't been converted, and offered the owner $600, which was about half what the owner said he wanted. Granted the pawn shop is only going to give you about 50%, I don't buy his statement about the gun being worth more if not converted. What say you?