Fake Marine Grade Plywood

[follybob]

I just bought two sheets of "marine grade plywood" . I had a friend pick it up. Now that I am looking at it, it is five ply and has multiple footballs and areas of filler in the top layer. Is there anyway possible that this is the correct material or suitable for a transom repair? I have a couple sheets of birch plywood from Lowes that is 12 ply and looks much better. Any input is appreciated.