They just started putting the pieces together. During my last trip between the 4th-5th, they built an additional wall in the Hulk / Bridge area to block people from a certain piece of equipment I'm assuming they're going to be using in order to finally start putting the track together towards the beginning of the ride. One day it wasn't there and another day it was magically there.
Whatever the official date might be, I think people will be able to ride before the official opening date they might announce. I only say this, because for the original first part of the Harry Potter project, I was able to have entry into the park and ride the rides several times before the official opening.