I know the pirate rooms typically cost a little more per night than the standard rooms. Do you know if you paid a little more?? That is one way you might be able to tell. I had booked a pirate room for my upcoming trip and had to specify that I wanted a pirate room but I eventually decided to upgrade to the Beach Club.
Also I am not sure but I have heard that all the pirate rooms are in the Trinidad building. I guess that does not help though because you will not know what building you are in until you arrive.