Its kind of hard to see here, but this Commander was hard chromed, and then used daily for over 10 years. It rode in a kydex holster for most of those years, and you can see where the contact points were. The black streaks are actually a mirror polished chrome, and not black. The rest of the gun shows very little wear or markings, except for some very light, "dusty" rust, around the left grip where it was against my body.
The above gun was originally a nice Colt blue when it came out of the box, and didnt last a year in a couple of Galco Royal Guards before it was badly rusted in a couple of places.
The only other guns Ive had that didnt rust at some level like it, were my later SIG's with SS/Nitron slides and my Glocks (although the slide stop on a couple of my Glocks have slightly rusted where the finish on them wore off).
Next to a good finish, as far as rust goes, the next best thing to sliced light bread is kydex!