i'd be interested to know myself. my understanding is they don't. but i'm a little worried about the little piece of plastic that rings the display. i've dinged up the one on my black 6 but you can't tell just looking at it, because it's black. wondering if that little piece of plastic can't get dirty or stained or marked up over time on the white phones. i would think it would stand out.
I have had a white iPhone 4s, 5, 5s, and currently have the white/sliver 6+. All have held up extremely well. I ordered a SG 6s+ this go around. I am hoping that it holds up as well as my white ones have. Just thought it was time for a change.
Yeah, I am finally switching to a white silver and I have been ordering black or Space grey for awhile. I was worried about yellowing and also the look of the screen against the white bezel, but I have seen quite a few in person and they look very nice.
I never had any issues with the white 4 and 4S that I used to have. Currently I have a space grey model because I wanted something different, I could see myself going back to white someday when I get bored with the dark colors.