I'd love to see it "in hand" through a loop but, short of that, although I can see what you mean, I'm going to say probably not. Interesting coin though.
The dirt has created what looks like a stain with a small letter or number but it's nothing. It's difficult to see unless you turn your head to the left as far as you can.
To date I know of no numbers or letters underneath any of the numbers in the date. There are no Overdate Lincoln Cents known.