Mine had a sticker right on the box (sadly, right on the front of the box, by the big 2).
Interesting, my box only has the S/N sticker and nothing else:
Wish we could figure out what all the barcode stuff means. Okay, that's not helpful at all, but this could definitely be a batch problem. The downside is that this early in release, we can expect the early batches to make up a majority of outgoing devices, and MS doesn't check outgoing exchanges for the build flaw, so if you try to exchange you may end up with the same thing. I don't know the best course of action on this one. Perhaps wait as more batches are produced, after ensuring this would be covered by warranty (yeah, nothing should rattle on this thing).