if booking call loews on 1-866-563-9792,
What jakey says is what i did, bought the membership online, i was already an RAC member but the money i was saving made it worth while. i.e hotel -food - and merchandise, although there is no AAA discount in the hotel restaurants, if i remember correctly.
You do not need membership number until you arrive, you can still book it, just make sure you have your card when you go on holiday.
Would not expect the rates to go down, only with APH ,AAA or Supersaver rates, you can cancel with full refund 5 days prior to arrival, booking through Loews ,not sure about booking through Universal site, as people have been getting different feedback booking this way