another p/t vs. regular plywood question

[MarksJoy]

I am going to replace the insides of the gunnels with new plywood and use new foam rubber padding and cover it with some kind of marine covering. The old plywood has rotted through in one area on both sides. once again, a pressure treated question. Should I use 1/2" p/t plywood as the sides or regular exterier plywood? If I use p/t I wont have to coat it with epoxy, just cover it. Am I right? The p/t should hold up to water.