on the latches, take the mechanisms all apart and clean them up - you'll prolly find rotten rubber bits and broken springs
the panel floor is indeed ply - an oversize sheet that GM designed for the application, and the individual boards used on the pu won't do for replacement - need more rigidity and flex resistance then they'd supply - if it needs replacement, you should be able to special order a piece big enuff
got pictures? we like pictures, and panels are my personal addiction!
Bill
