Question on Mustang fiberglass floor pan

Started working on my floor pan yersteday and I have a question for those who have had theirs out. The toe board is backed by plywood bonded to the glass.Naturally it's all rotted so I am replacing. But the panel that goes from under the motorbox to under the back seat was missing most of the wood. Am I correct to assume that this panel like the toe board needs to be completly backed up with wood? I'm thinking it does but want to check. Thanks

Thanks Tim.I am going to leave the 1/2" floor that I have on there now after I remove the carpet from it. The reason I ask is because if you look at the bottom side of the back panel,you can see where 1/3 of it by the exhaust cut outs looks like it had something bonded and the rear of the panel had what looks to be a 6 x 14" piece. I think I will do the aft panel the same as the kickboard.