Can anyone tell me the name of the bluing used on the rear sight spring.....I believe that is the part I am referring to, I remember it had a deep BLUE color, and was done with a different process than today's 'rust bluing'

I was curious what pros/cons there might be to that process I am referring to.

It may just be a 'heat blue' or basically the temper color achieved when heat treating the steel. If you polish the metal part, then fan a flame under it (I've seen it done by using a piece of aluminum can under the part and fanning the flame underneat to get an even heat) until the desired color is achieved. It will reach a straw color, then a bright blue, then down to a plum color if you go too far.

Yes Matt, I believe you are correct, I was thinking that was it, a 'fire' or 'coal' I know it seems there is a term for it, but I am curious as to why that part would have been blued differently?

Perhaps the metal properties were maintained or enhanced for the 'spring steel' properties, none-the-less, I guess that process works to also protect the metal from rust? I believe it was void of any when it was removed on the gun I sporterized.