I don't have a dog in this fight (if they're is one
) but I will try to answer some of your questions.
1. Source for Colt's bluing: Equipment and salts come from Du-Lite Corp; 171 River Road; Middletown, CT. 06457 (
www.dulite.com). Unless recently changed. They first set up the system shortly before WW2 because it was specified in some government contracts for certain parts that were not to be Parkerized, and Colt stayed with them after the war. All handguns that were blued were processed through the Du-Lite system. Difference in color between the various grades (Standard, Royal Blue, etc.) was dependent on how the parts were polished.
2. Colt buffers (who were among the highest paid shop workers) were equipped with special buffing wheels that were contoured to fit the particular part(s) and came in sets with different levels of abrasive. While this was true of all models, today only certain ones are still in use. Obviously the 1911 platform is one of them.
3. Value of refinished guns: It depends on the particular model and when a particular piece was made. From a serious collector's point of view, ("Serious" means they have lots of money, but are very picky about what they spend it on.
) refinishing detracts from the value - and sometimes substantially so if the refinish doesn't
exactly duplicate the original.
In your example - a Python - it was originally blued using the Du-Lite process. A factory refinish doing the same would slightly reduce the value. But a Du-Lite factory reblue on a handgun made before that method was introduced at Colt (approximately 1940 or 41) would in the judgment of a "serious" collector, be unworthy of spending top-value money on, and if you take what someone would pay - less the cost of refinishing - you could lose money.
In the case of the Python, you might find buyers that weren't serious collectors; but it would be harder to find someone otherwise who was interested (as an example) in a WW1 .45 1911 pistol, if you are looking at it as an investment.