I SM-ed and then called, with no luck. (Seems that Amex has become extremely strict about not modifying offer terms after you apply.) Then I called again, spoke to a supervisor and reasoned with her it was like a bait and switch, and an applicant has no way of knowing that there are different offers with different terms. She pulled up the 45k offer but it showed that it expired 12/31/12. She was unable to pull up the 40k offer, since there is no code on it, and she said that it looked like it also expired a month ago. (I told her the terms say it's valid till 3/3/13.) In the end, I convinced her to bump me up to the 40k offer.
Bottom line - Amex is very tough with this now, but a supervisor can make it happen...