We really wanted the Dalmation section. I called a week before and 'reminded' them I wanted that. They said that the rooms still hadn't been designated.
I called them again two days before and 'reminded' them again. They said that they would put it in the system again.
We got there and.....we were in Dalmations!!
So it pays to be persistent and remind them!
(and this was in August, busy season, with two rooms, one for us and one for our other family) and we still got it! Be sure to tell them that your son is a huge Toy Story fan. It is funny, when we got one of our things in the mail from the Disney Travel Company with our info on it, beside our room it said "Kids are huge Dalmation fans" So they do put these things in and consider them!
Good luck, I hope you get what you are hoping for!!