SAM 1911 grip screws

I picked up a SAM 1911A1 pistol (marked "M1911A1 US ARMY") and quite frankly, it's a nicely done handgun (imported by PAC, Modesto CA).The only real difference from the GI parts kit is the grip screws, which screw into the frame instead of a bushing as on the GI version.Anyone have info on these? I can't identify them (thread/pitch). They seem to be M5 and a TP of 0.5 mm but I'm not even sure if they are metric or not. If anyone can help, I'd appreciate it.thx