http://www.gameinformer.com/b/news/archive/2011/01/26/the-art-of-skyrim.aspx is where decals were mentioned. It is correct that "armor decals" was never said, only decals. However, decals are something you put on objects, not people. It, thus, makes total sense that it would be armor or weapon decals. You can't decal a person, because that's a tattoo.
Hmm. I guess I got a little excited and assumed that it said armor decal. Haha, woops!