“The 1894-S Barber Dime could be construed to be like this, it wasn’t authorized to be issued from the SF Mint, but the director had the dies on hand and polished them to make 24 specimens for visiting bankers. “
Theoretically, these could be seized under existing laws concerning coinage, but I doubt if it would be perused. There are a few other “semi-mythical” coins in this state, from what I remember when I enjoyed coins as a hobby.
I suppose that the only way to really force the legal issue would be to try to buy something with it, maybe also using a 1913 Liberty nickel in the purchase!
I’ve visited a mint (the Denver mint), and I think they designed the place so that someone is always watching everything. Otherwise, many “strange oddities” would start to appear in collections!
There’s an independant mint operating with a restored press from the Denver mint bought at surplus auction. I couldn’t believe the blanks and misstrikes the guy hauled out of the guts of the thing, hundreds of them...