Yeah, it's actually showing now for Fri & Sat nights the first three weekends in June... nothing for the rest of May unfortunately (or the last weekend in June).
Incidentally, the AAA rate for weekends in May is $118, but it is not prepaid and allows cancellations up to 24 hrs in advance. In addition, paying with Costco certs actually brings the rate down to less than this sale rate ($98 vs $99). Alas, you would not get the extra 2,500 pts though.