Hey Abe, it was bought on the Empire website, remember you mentioned that site to me when I first joined here asking for a 20c. Nothing was ever said on the site about this S though.
I noticed, several of my other purchases turned out to be R3's and R5's. Got some replies to this coin on CU, seems fairly common & doesnt bring a huge premium. Still a pretty cool find with a loupe several months ago.
It is a repunched mintmark. It may be the one listed in Breen's Encyclopedia as #3875 the $ variety "Obvious extra serifs at top and bottom of S simulating vertical line in $. Mintmark first entered leaning crazily left and then corrected." (No pictue)