[GaryVoshol]

First off, inspectors aren't going to see it. They will only see the back of one sheet of plywood - because your material is covering all other parts.

And what is plywood, except glued together thinner sheets? I can't see any reason we can't make our own plywood out of other materials, even if that material is two thinner sheets of plywood.

Now, whether it is wise to use it or not - That depends on how you are fastening your material around the wood. Are you using angle aluminium screwed into the wood? If so, are you screwing into the ends of the wood? You may want to have commercially glued 3/4" plywood rather than relying on your own glue.

I guess the real question is why you want to bother? Just go buy a sheet or half-sheet of plywood.