First I would use a mild paint stripper to see what the original finish looks like as the worn areas on the painted finish are probably in the same place as the original worn places. Try something like lacquer thinner first as it works very slow. A 1911 with only 10% original finish is 10% more than a refinished 1911. As far as restored goes, the original finish was an oven blue finish done in either a coal fired or gas fired oven containing carbon from charred and powdered animal bone. If you just want it reblued, a modern hot salt blue will certainly should fill the bill.