~~~ where the original obverse; 100 AA, had a blank reverse where the crude 100 was later engraved

The reverse was left blank while everything needed to be known on the obverse which wasn't uncommon to keep the cost down as seen with all those uniface personal sets.

I am looking for the blank reverse of this... which might be at the FUN Convention this week and I am willing to pay 2x of what the altered piece lists for at eBay.