Unusual to find one of these counterstamps on an old Merchant Token. They are usually found on more modern coins and are placed there as vending machine test coins.
Mike
Master Referee - See my profile for what I collect.
This is actually not an "8" but two (or three) circles punched side by side. It's possible that the "puncher" wanted to make it look like an “8”.
We see this kind of thing over coins in all periods, but especially in the 19th-20th centuries. All the time I see eBay sellers trying to pass such things as legitimate counterstamps.