I came across a Ontario (or maybe Camilius) USAF issue type of leather sheath with the blued metal sheath backer, you know, for the Pilot Survival Knife. Well, I need to finish installing about half or more of those black domed, 1/4" or 6mm (I think?) single sided rivets, including through the metal backer. Does any of you all know what the correct rivet is (could it be a small semi-tubular one?) And where I could get a few?