Back in the late 70's and early 80's my father had a business restoring antique slot machines. When he stopped in the late 80's he kept two tool boxes of tools he used. He downsized his home recently and I found those boxes and brought them home. I can identify all but, this one item seen below. I sent him a message and asked if he knew what it was for. He didn't remember and thought it was for stamping the payout discs. I know that is not correct as there are two of the payout punch kits in the boxes and those are not the same.
There is a very slight chance it doesn't go with the rest of the tools but, I do remember seeing it on the bench with the other slot tools when I was a kid.
Let me know what you think.