Re: Popular ways to mill sights off surplus arms in the 50's & 60's?
Removing the "ears" of the M1917 rear sight and filling in the hole in the receiver ring was common practice in the pre-and post-WWII era when "sporterizing" those rifles. There was not, however, any consistency or precision in how it was done, each gunsmith basically doing it his way, and often differently each time.
The best way to determine what scope mounts to use (if that is the goal) is to find a gunsmith with an assortment of Weaver bases and use a collimator to get the scope lined up with whatever base(s) will work best. That sounds very difficult but actually doesn't take long, though it is a bit of a PITA.