It looks like a normal 1923 Wheat to me? Where do you see the S? That is one dark wheatie! There are others though that can help you better than me! Way better me. Pheonxi
It looks like as "S" to me. It is in the right spot, right size, and right shape, but it is so faint that I cannot be sure. It took me a bit just to see what you were talking about.
I think someone with a skill level a little below Billzach's has removed the "s" for use on an '09 vdb cent.