I picked up a plywood pallet behind a store because it had what looked like baltic birch ply for the deck. I needed some to attach wheels to and sit a tool cabinet on top. Got it home cut off the side stringers and looked closely at the wood. super thin veneers of something like birch or elm. The main body was between 7 and 15 layers of something. I think they were trying for 7 plys with a face veneer on each side. About 5/8 or 3/4 thick. It is not like a laminated core door. Just random waves and creases in the core. I was able to get a small piece good enough for my use the other 3/4 of the small sheet is junk.
Bill D