On Dimes, Philly dimes do not have a mintmarks until 1980. (Proof or business strikes) Since 1968, the proof dimes have a 'S' mints. Before 1968 The proof coins where struck in Philadelphia.
During the 1965-1967 all coins were struck without mintmarks from all three mints. SMS proof coins were from San Francisco without mintmarks. In 1968, the Proofs were supposed to have 'S' mintmarks, but some Proof dimes didn't have the 'S' mintmarks on the proof dimes.

1982-P Business strike dimes were also found without the 'P' mintmark.
So the 1975 dime above is a normal business strike dime, with no mintmark, because if was from Philly.

But these will be proof dimes, not business strike dimes. Hope this helps.
During the 1965-1967 all coins were struck without mintmarks from all three mints. SMS proof coins were from San Francisco without mintmarks. In 1968, the Proofs were supposed to have 'S' mintmarks, but some Proof dimes didn't have the 'S' mintmarks on the proof dimes.

1982-P Business strike dimes were also found without the 'P' mintmark.
So the 1975 dime above is a normal business strike dime, with no mintmark, because if was from Philly.

But these will be proof dimes, not business strike dimes. Hope this helps.






















