Pressure Treated Plywood?

[fishingwithblue]

I have a piece of 1/2 inch ply that came off my duckboat I want to use for the fuel hatch repair. Problem is the man who sold me the duckboat said it was marine grade ply. What if its not and its pressure treated ply, it wont do right with the fiberglass and resin.....right? I dont know how to tell the difference in marine grade and pressure treated. Everybody uses the words "marine grade" when they are trying to sell a boat.