Definitely cannot tell from the images provided. Do you have a magnifying glass you can shoot some photos through?
Is such a thing known? I think it is not possible. Why would there be an S out there at all?
The S mm was last used in 1955 and not reintroduced until 1968. What is the likelihood of a 1964 half having an S over mintmark?
Can't tell anything from your pics
D over S: impossible. D over D, very possible. There are several known varieties.
The SF mint had been shut down for nine years at that point, so no Kennedy half die would ever have a reason to be punched with an S.
It is not possible to verify or negate conclusively from those pictures. It is, however, unlikely. Cheers, RickO
You really need to improve your pictures. Try first to show a normal picture of the mint mark like you do of the obverse of the coin. There is only one poster on this site that sees things on coins that the rest of us cannot.
Kennedys are my quest...
The San Francisco Mint was in mothballs at that time with no thought of reviving it. There would have been no reason to punch and "S" into the reverse die.
Hi and welcome aboard. The RPM, no. A misaligned planchet, maybe?
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