Yes, I did think that at first, since that's usually what happens around here. That said, your link does say they bin them, so my bad there. I was under the impression they were just sort of bumping up the clocks of the HD 7970s on reference cards in general, but it looks like it'll sell alongside the old revision apparently.
That said, the HD 7970 almost universally handle the GHz mark just fine, so the binning can be anything from super high bins, to just filtering out the poorer samples that just don't handle the GHz mark. That's not a huge portion of them, really.