We have had really good luck just requesting a building during the reservation. We also take an early flight and check in around 12-1 PM. We have always received the building and floor we requested during the booking at the Poly. I must be in the Tahiti building when I stay here.
Its really a nail biter hoping you get your request and I have read alot about people faxing special room requests. I think it really frustrates the room assignor and I do not blame them-people can be really picky even down to the room number and location.
The best bet is to make the note during your booking. I would not want to be the fax that makes the room assignor mad that day-if you know what I mean. You may get a bad room lol.
You do not always get the location you wanted, the resort can only please so many people. Some are going to be unhappy and if you are really unhappy voice your opinion to a supervisor, but remember room requests are not guaranteed. Good luck and have a great time