I think it really depends on how busy the hotel is. I am Loews Gold and stayed in a King Suite during Presidents' week. I paid rack rate for this suite and was unable to upgrade. I asked about upgrading to Club Level and was told "sorry -- the hotel is booked solid." So, my advice is, not to count on anything. If it happens, great, but if not, don't be disappointed.
I have stayed at Hard Rock, Portofino and RPR and have never been offered any kind of upgrade. It's the luck of the draw I think.
Have fun!