Finally determined my Colt 1911 front sight is indeed...
staked in place too far to the left and that is why my rear sight has to be drifted to the left enough that it slightly overhangs the dovetail cut. I couldn't figure out a suitable way to measure it with a dial caliper that was consistent from one side to the next. Finally, it occurred to me to just lay a string right across the middle of the barrel and the recoil plunger and see how it aligns with the front sight and it is unmistakably and most definitely to the left of the barrel centerline. So, unless someone makes a front sight with an offset stud/stake (whatever it's called), I guess my only choice is to have the slide dovetailed for a front sight. Now I just need to decide who to send it to. I'm not too upset about it though....I consider three dot sights something close to an abomination if they are not tritium. I want plain black serrated sights.