Everyone should re-read my post above. The hotels are owned by the same owner as the casino and its site. It is not pre-paid, as far as I know and the hotel is chosen, so not a grey booking site.
Since OP stated that he can now see his stay online on Marriott.com and they took his number, it augurs well that he will get points. However, it certainly is at the discretion of the property inasmuch as the rate was not booked on Marriott.com and therefore they are within their rights to deny him same.