I just picked up a 1920 in good shape, but with a side plate the seller described as a mismatch. Upon receiving the pistol, I'll admit that I've never seen anything like it. It looks as though it was set upon with a file and a Dremel, then buffed and hot-dipped blued. It has a matching number on the lower side that has been mostly buffed away, but sure looks original to me. I think it's the original side plate, but can't imagine what happened to it. The pistol has no import marks, and has over 80% original rust blue.