Nope... you won't know your room number until you've checked in and your room is ready for you.
Even if they have tentatively assigned room numbers in advance, many things can happen to change that... the previous occupant could extend their stay, mousekeeping or maintenance could find problems with the room that make it unavailable until resolved, problems in OTHER rooms could cause them to shuffle guests around. There are many reasons they won't give you your room number until it is actually and officially "your" room.