According to the rules you should not get night credit for two rooms, only one, specifically the one you are staying in. If you are going to pay for both rooms, then you should get the points for the spend on both rooms.

Now that's not to say the property won't mess up and post each room separately giving you credit for both as individual stays. MR may review your account and pull the posting. Do not count on the nights staying and plan your status renewal accordingly. Hate to miss status because of an error in posting.