I have a Circa 1913 Colt Officers Model with the elevation adjustable front sight. I am looking for a replacement, as it's badly boogered. Problem is, only screws I can find are too small in dia. This looks to be about a #12 in dia. On my .22 O.M., the screw is much smaller in dia. Were there two sizes of these adjustment screws? And where might I find one? Thanks!