Sometimes the phosphate gray guns will have a faint rusty haze on them. Mine was like this when I got it in 1997, and the first time I cleaned it I oiled up the phosphate coating and had reddish-brown patches afterward. I've never liked the idea of letting phosphate protect the metal alone, without oils, but some guys do this, I hear.
Oddly, after years of oiling my pistol's exterior, it can sometimes look almost black now instead of that odd phosphate greenish gray. A fresh coat of oil (and wiping off the excess) usually brightens up the gray again. Like in a car's motor, gun oil can oxydize when it's protecting a gun in the gun safe for months on end, and it gets darker over time. Better that this oxydization happens to the oil than to the finish on the gun.
Scott
