That is a really nice piece. Definitely best to keep the original finish. Re-bluing never bodes well for resale value. Not that one plans to part with something like that!
This will be controversial, so don't read unless you're open-minded. Concerning that very nice Colt. If it were mine, I would consider cold-bluing it, with no surface prep other than hot soap and water. As you know, cold blue is not hard to remove and is very easy to 'distress' or 'age' without affecting in any way the original steel surfaces. The point would be to have a more authentic-looking gun that would easily and quickly wear on the high spots for a great 'old' look. Cold blue can be nicely done in the right hands, but it does take some knowledge and experience. The only reason I mention this is because I'm getting ready to do just that to a 1918 Colt M1911 that has not one speck of finish remaining on the slide or frame. Its not extremely valuable either because of some very light pitting, worn-smooth grips and a pitted bore from early corrosive ammo and no cleaning. I'm going to put new grips on and age them back as well as a cold blue job to just make it more presentable. If anyone wanted to have it restored in the future, everything would be there just like it is today - pits, rust stains and all.
If I may sir, I'd suggest a "brush blue" finish, which was correct for the era. The parts were brushed, but not high polished, which gave the blue more of a satin finish than a deep blue finish that Colts are famous for. It tends to wear off the high points, which give you holster wear while protecting the rest of the gun. An unmessed-with M1911 is an expensive piece, particularly if it is an all matching GI duffle gun.
R/S
Fritz