D Crockett is giving some excellent advice.
If it has numbers, run 'em with the sherrifs dept. If it comes in stolen ask them what they want to do to make a bad situation good. I'd rather be out a few hundred than caught with an unknown stolen gun. At worse, somebody might get their stuff back, you'll be out a bit of cash, and the local LEO's will know you as a responsible person. Win,win.
Could just turn out to be an old guy liquadating something he'll no longer use.