Which coin ? And on a side note, is the 1974 Aluminum cent legal or not to own/sell ? Not the 1974-D, but the 1974 one given to congressmen.
I haven't checked how complete this is but I do know there is this https://www.pcgs.com/SetRegistry/louis-eliasberg/imagegallery/1162
Either the 1822 half eagle, or the 1870 S three dollar gold, I forget which one, but I'm fairly sure it's the 70-S. No the 1974 Philadelphia aluminum cent is NOT legal to own (at least according to the position of the government. They say they are all still US Government property.)
Neither of those appears on the PCGS page, which I guess isn't surprising if they're permanently off the market.