Hey Ray, Welcome Buddy ! I know it's hard right now but can you get some closer up pics? I highly doubt it's a S/D but it could be umm. something , right?
I would use a program I use to edit . It's called "Photoscape" ( FREE DL ) . 1) Take pic with cell phone . 2) Open with program the crop in circular pattern, adjust size and lighting if need be , save to file.
Lunapic is also good, also free, and no download necessary. You can edit online with it, then save the pic.
It takes a little while to learn to use Lunapic, but I've grown to really like it. It's worth fiddling around with to learn a bit. Quite useful.
This reminds me of going snipe hunting when I was a kid they gave me a guny sack and pointed me towards the woods as I was yelling Snipe! Snipe! They took off in the car
What you are seeing is a well placed die chip. It is a common occurrence more so on the S, but can be found also on D and P mm.