I think there was a more recent reference to it being 85+. It might have been in that thread about the T4 raid loot / HA issue. My guess would be certain aspects, like the anniv stuff scaling down to 85, while other aspects remained solidly 100.
Will there be any reference to the delayed opening, or the broken stone, when the zone goes live? It would be funny to run into some NPC hiding out because he accidentally locked everyone in (and out) for a few years.