No link to thread?

The 1950 Truck Data Book Supplement describes:
Single Unit Body Floors (panel and canopy) - changed to 1-piece 5-ply

From a the Light Commercial Vehicle Association (LCVA), Jan/Feb 1984 (which I think later became This Old Truck, and is now Vintage Truck):

"1950: . . the floor boards of panel and canopy express models were changed to plywood construction. In the new construction a single panel of wood and five skid strips replaced thirteen floor boards and twelve skid strips. The new floor was positively sealed against dust leakage and the plywood made the floor 25 to 30% stronger than the former construction. "