Randy,I once owned a 20g NID that had an old sales receit in the stock.It was from the Clevland OH area,it had an old 4 digit telephone # on the heading.The original owner had a scribbled note curseing anyone who sold the gun.
I also had an old 20g Model 21 with the original owners WW II draft card in it.The first thing I do after a gun purchase is check under ther buttplate.Dave