David...I am in complete agreement with all you stated above. The sight base on a RM that has a blade mounted later (since a choice of several blades was available)should have been pinned to the barrel ramp, polished flush and then finished in blue or nickel. The last operation would have been to pin on the sight blade and that is why all RMs I have seen have this pin exposed (not polished). In the case of where the ramp and blade are blued, the ramp would have been pinned to the barrel after finishing so the pin would be exposed (i. e. not polished flush to the rib). Same situation is seen on 44 Magnums and other target models through the mid-60s.

Bill