Great project, and thanks for taking the time to explain the process in such detail! I'm not a 10mm guy but do have a 'project' 4013 of my own to get fixed up, and this has been a very informative thread.

I had the same problem with the rear XS sight on my 457, they make them a bit too long for sure and I had to file mine down.

I've also used Caswell Black Oxide on a few smaller 3rd Gen parts, and it seemed that the Stainless Oxide worked better than the Non-Stainless for me. The carbon steel parts turned out kind of grayish, and would leave rings around touchup spots (overlap on the factory blackening). I was also surprised to find out that my 6904 slide stop was actually stainless steel - thanks Caswell!