Color will fall off
Rose gold will fall off, anodic oxidation process on the color of the paint layer is very thin will not be a piece of a piece off but will wear off.
Gray and silver color loss of very little, rose gold is the most serious,
My friend 6S just came out that will buy the rose gold, with less than a month of color, change back to the deep sky gray to the present did not fall off
References
Rose gold paint, really the day of the dog . Wizards.com[cited 2017-12-28]