20 plus years ago I sold a model 59 and 586 to a guy. I purchased the 586 new so original paperwork was on me. A year later the FBI agent was at my job because the DB I sold them to went and robbed a bank and shot someone , got shot, and killed. I was very happy to hand that fbi agent the BOS that documented the date that I no longer owned that gun. That's why I do them if I sell to someone I do not know.
Wonder what would have happened if you told them you sold it..wish them a nice day and close the door?