Yes, you still have a shot. Here's why:
As the sailing date approaches there is a team down in Miami that "reserves," for lack of a better word, staterooms. These reserved rooms are filled in a variety of ways (special guests, Casino offers, and MoveUp) and they are hidden from the general public.
Another reason could be that certain travel agencies like are holding space yet to be filled. As the sail date approaches this unsold space is released but may or may not appear for the general public.
If you're interested in a higher category stateroom you should submit your bid, the worst that can happen is they say no and you have some extra money to enjoy on your vacay!
Cheers 🙂