I'm just getting ready to do a roll on bedliner in my new truck and I'd think that using pressure treated plywood AND roll on bedliner is almost redundant... bedliner offers so much protection why would you
need pressure treated ply?
If I were going to go this way I'd apply a coat of roll on to both sides and all edges of ordinary plywood...
You might want to round off the square edges of the wood a tiny bit first though... just take the edge off with sandpaper so it's not a sharp corner and your end result will be a lot better...
With ANY finish you put on wood it is always thinnest at the corners and rounding them a bit allows whatever product you use to flow and remain thicker at the edges which will prevent moisture from getting in and ruining the wood over time...
Hope that helps...
