Right but you asked about the "S". There is one in "TRUST", the mintmark, the one in "PLURIBUS", and two in "STATES". Which one are you asking about? Regardless, the coin is just dirty and circulated. So a bit of both.
A very interesting coin nevertheless. Issues from 1944 to 1946 are said to be made from used brass made from spent wartime shell casings. You’ve got an exciting piece of history there!