I believe your answer would be 406.3 D (3) in the '08 Belgariad
You'll need to get into a few older code cycles to see the evolution of it all, but the markings 'No Equipment Ground' and 'GFI protected' have been around for a while
These stickers usually come with a GFI, in with the paperwork. Myself i find they just don't last, and who would want them say, in a high end kitchen?
A while ago, one of our inspectors here bagged me on a basement receptacle not being labeled. So i asked, "can't i just write it on the 4 sq cover?" to which he responded "I don't see why not, as long as it gets the point across"
So i just wrote on it with my sharpy, done deal
If one really thinks about all the protective devicing in a dwelling, afci's and gfci's, or even gfpe's , it'd be mighty hard to label every one of them