I just came across this 1971D in my first stab at roll searching last night. I've just picked up the hobby again after letting my books sit for about 15 years without being touched. This coin seems to be much more brilliant and a much higher quality strike than the typical coins for this period which leads me to think it could be a proof. Am I out in left field on that?
Oops...after I posted it I thought I'd go look to confirm proof was an option, and came back to edit to not look like an idiot noob. Guess then I'm just showing off my find.
They do make Proof Like coins almost every year. There are several ways in which a coin intended for circulation can end up being like a proof. Ironically being struck twice like proof coins isn't normally one of them. PL's from that era are usually the result of the die being polished and/ or basined. Basining is grinding the die faces flat yet slightly convex. These appear to have been intentional in order to make high quality coins but there are other possibilities. Dies do get different treatments dependent on their ultimate use and those being prepared as proof dies can end up for other purposes such as mint sets or regular production dies. PL's in mint sets are not at all uncommon for most dates and '71-D are nearly common (~2% of production). They weren't terribly uncommon for circulation either but I doubt it was more than about .01%. This is nearly impossible to know but I have seen these before. PL's are sometimes just well made coins struck on polished or partially polished planchets. On rare occasion you will see coins that look like branch mint proofs. This especially applies to post 1986 mint set coins that are made at lower speeds, higher pressure, and with newer dies than others. It the die was also basined as isn't uncommon and burnished planchet was used which is quite common then the coin can look just like a proof. This particular coin does look pretty PL. Normally I would expect it to be a mint set coin but this particular example doesn't have all the diagnostics (particularly the even strike) so I suspect it is not a mint set coin.
