Afraid not, the only novelizations of the two films are the young adult versions. I can understand why they may not have wanted to do an adult novel for Curse of the Black Pearl, since they didn't know whether the movie would do well or not. But no adult novelization for Dead Man's Chest?
but they do have a series (sorry, I don't know the name) about Captian Jack when he was a teenage stowaway. I don't know if they are adult or not, but they're out there and would probably be an interesting read.