lots of these trucks have wound up with ply for the bed floor, frequently just laid over the old one - note that the size of the bed floor doesn't quite work for one sheet, so you'll have a seam somewhere
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics