I mean, would you really think that they wouldn't have expansion pads set up at the start?
I would think that Universal wants to have enough space to add in another world or two, after the park opens. IOA went to that extent, where Jurassic & Lost Continent had plots pre-Potter. And if I'm not mistaken, Seuss still has their plot next to the CiTH show building.
Id assume, expansion plots are likely gonna be around.