Odyssey 175 SS decks

[carpcatcher]

I'm helping a friend do some mods on a boat he just came across. It is an Odyssey 175SS made by Forest River. He wants to lighten it up some so he's looking to replace the plywood decks with aluminum. The problem is we can't figure out exactly how the carpeted plywood is fastened. The carpet is rolled under the edges so it wasn't put on after he plywood but there are no visible screw/rivet heads in the carpet. Does anyone have any experience with this brand and how they do things?