Coleman Scanoe missing flotation/rear deck

Hi all,

I just bought an old Coleman Scanoe - the older kind with the metal tube internal framework. It has a small compartment fore and aft with flotation in it, except that the stern compartment and flotation is missing. Any ideas where to get replacement parts for this old square stern?

I’m sure I could come up with some other solution for flotation, but I kind of want the deck pieces in place because I think it’s part of what provides some structure to connect the whole rear end to the metal framework and keeps the weight (and thrust) of the motor from deforming the plastic.