I've pilfered through 100's of these over the years but a first grab out of a fat sack an XC {3rd from rarest being MV and MM} 25% off center. Made of pressed fiber (paper). Has been patiently waiting since WWII to be found....
These are neat and as you have learned can be found if you look through quantities of these. These off-centers aren't made the same way as they are in coins. The OPA tokens were first impressed on sheets of the fiber board, and then the tokens were punched from the sheet. So the off-center is actually caused by a mis-fed sheet that resulted in the punch being in the wrong place.