Oh so it was drilled for the B & O, then they slapped a sort of half-assed keystone over the old hole. Got it.

Ludwig is known for that kind of thing.

So now you have corroboration as to the origin and timeframe. I still think the bottom hoop is incorrect, but it really doesnt affect the drum or its value much. The rim looks to be an older, no neccessarily Ludwig, possibly chrome over brass, as i dont recall seeing the snare holes being that way after they changed to steel.A period correct bottom hoop can be had for fairly cheap.