Well over forty years ago I traded away my first Marlin 39A-- one of the ones with the old fatter forestock. Don't even recall now what I traded for. Bought my second one, which I still have, not long afterward.
Sales are another question: I sold a beautiful pre-B CZ-75 to buy something I thought I wanted worse. It was a nice GP-100, and I'm a revolver guy; but the Rugers are common, and older CZ's that good are rare.
Also sold a nice Smith 459 I wish I had back. Don't even remember why.