I believe that the "S" mint mark style is only for Proofs only. Common circulated SBA 1979 "S" don't count....sorry Hopefully this true ... can others chime in on this ???
That is why I asked my question. Mint mark looks like a filled S but the coin doesn’t look like a proof.
My favorite teller called me a few days back and said they had a boatload of dollar coins including SBA. I very politely thanked her and said I don't care for them.