I personally don't see it. I remember a big hubbub last year when we thought that we were seeing black walls in TrT and then they got theming not two weeks later. Now, granted, there were a ton of black wallz last year, but I don't think we should be worried yet.
I do think there's going to be a big Klownzilla head at the end, but I think it'll be more like the classic "black hallway finale scare" that we saw in mazes like Poltergeist last year.
EDIT: Now that I think about it, that big triangle section at the end makes me think there's gonna be a big showroom at the end with a Klownzilla puppet, not a black wall. Maybe that's wishful thinking?