Comp'd or Free rooms booked on the internet, only guarantee that
some type of room is free not the category you requested. I booked a comp'd room at Ceasars Palace in the Augustus Tower but when I checked in I got a room of "lower" status. Most of the time, for example, weekend comp'd rooms at Ballys Atlantic City booked in the Tower will have you placed in the Claridge or the Dennis building.
They tried that with me too. Harrah's website brought up 4 different kinds of rooms at CP, all at "Comp". I picked Premium Palace Tower Room (never saw it at comp before).
Got there, check in clerk tried to put me into an Augustus room and I held my ground. I eventually had to resort to showing the printout from the website. She said that "preferences were not guaranteed", I pointed out that the "preferences" statement alluded to smoking and bed size. She went to the back room and when she came back I got my room.
Baccarat King later told me that nothing was guaranteed, but I don't see why they offer different classes of rooms on the website if they are not going to honor it...