You're worrying too much. Worst case scenario is when you check in, you request 2 queens and get charged for the 2 queens.
I had the same issue as you last time, and just went up to check in, asked nicely and was put into a 2 queen room with no charge. I tipped her $20 afterwards for the help.
Also, you can request for a queen cot as well if you really need to.