By the time BLT opened on August 4, 2009, Disney Vacation Development had declared 47.97% of the resort for the DVC inventory. This meant that on opening day DVC members could book up to 47.97% of BLT using points; the rest of the resort belonged to Disney to use as it desired.
On opening day, construction was essentially finished on all BLT vacation homes. Although DVD had only declared 9 Grand Villas and almost all of the two-bedroom vacation homes from the 1st floor up to the 7th floor, DVC members had access to all vacation homes on all floors because of the Reciprocal Use clause contained in the Master Declaration. The Reciprocal Use clause permits DVC members access to undeclared vacation homes belonging to the developer. In exchange, the developer gets access to declared vacation homes that are part of the declared DVC inventory.
I suspect that VGF will open in much the same manner as BLT. Depending on how well sales go for VGF, I think that by opening day about a third to half of VGF will be declared for the DVC membership. But, like BLT and its Reciprocal Use clause, I imagine DVC members will be able to book any vacation home at VGF, as long as we don't exceed the percentage that has been declared. I'm optimistic that the entire resort will be finished and ready for occupancy on opening day.