I do not have the original filler, but I've done two different ways to fill the void. My first attempt for one of the rifles I took the hinge portion of a ChiCom buttplate and the other one, currently what I use in my match prepped M1As, is using a rubber buttplate, cut it and trim the piece to fit.Any tips on how to obtain a filler plug?
Here is thread you can check out. The filler I cut out from a rubber buttplate is a close forgery of the real kind.Hytekrednek or Bamban, any chance you could post a picture of the metal GI fillers? I've never seen one. Does it look like something that could be easily reproduced?