Here, it looks like a 5 in the middle of a star. Except it's small and hard to see. Maybe I'm imagining it, I don't have my magnifier and it was 6am when I had it in-hand Admittedly it's not a series I collect, so it's out of my wheel house
the star shape is actually caused by the design. The left and bottom are hair lines, the right is cheek. The "5" is probably a well placed ding. Richard
Most of the counterstamps that have significant value are the ones that have an identifiable advertiser. That said, I would have bought the coin for resale at that price but I love Bust type coins.
I bought a counter stamped "9" or "6" bust dime at the Baltimore Whitman show last year. I've kind of been wondering why it would have gotten that stamp. Mine was also around $20
Looks like there's a "W" on the left wing, as well. Might this coin have once visited West Point? ... just kiddin'