Clipped planchets are not uncommon on Civil War and related tokens. It's neat, though. As to the specifics of that particular type, I'll let the more specialized and experienced exonumists help with that.
I'm leaning towards a legit edge clip. The weakness in the RE may be a Blakesley effect, and the Rev rim around the flat spot looks more like it could be struck on a clipped planchet. Not positive, but that's what I think. Check to see if you can see any evidence of lines/scratches due to grinding or filing on the edge (which would indicate PMD). The token itself is a Patriotic Civil War Token Obverse 244, Reverse 381. Fuld lists it as a common type
