WOW, how timely is this post! I just finished doing a trigger job on a Ruger 1911 also and sat down to my computer to see if anything was going on on the forum. I don't know about the black coating but it does come off easily where you have to polish surfaces.
This one started with 4 3/4# plus a little wiggle (my NRA weights only go up to 4 3/4#). I also took the hammer hooks down to .020 and polished them. Put the proper angles on the sear with my sear jig and polished. Bent the sear and trigger spring back a little, reassembled and came up with 3 3/4# trigger pull. Disassembled, tweaked the springs a little more and ended up with 3 1/2# exactly (that's what my customer wanted). I was impressed by the quality of the parts. I felt they were equal to Kimber and Colt. Taurus parts are junk and Springfield are not much better than Taurus.
I'm sure the quality inspection will vary gun to gun, but on this one example I would recommend Ruger 1911s to anyone.
Mike

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Mike
S&WCA #2470