Quote:
The 1964-D has the mint mark on the reverse, so it wouldn't be a proof die, unless a hub for a proof reverse 1/2 dollar got sent to Denver by mistake.
All of the ies were made in Philadelphia a that time so a reverse could be hubbed with the proof hub and then stamped with the D mintmark.
Has there been any work done to see if there was a different hub starting in 65? The quarter dollar has different hubs for 64 and 65. If there was it should also be watched for on the 64 and 64 D since they were boh minted well into 1965.