Nah, I actually think this question came from one that might have read the manuals, this is not necessarily very clear from reading.
Right now I'm devloping with the P51c668 and using P0 and P2 with great joy.

ONE WARNING:
Some emulators require that certain pins not be manhandled, typically p3.6 and p3.7, if you plan to use an emulator make sure you know if that is the case.

Have fun,

Erik