I think that the 54/55 Chevrolet pick-up truck tail-lamp lens was plastic.
I think the 54/55 panel body tail lamp lenses were glass (on the lamp on the panel/suburban rear door, and the canopy express door/end-gate, and the suburban end-gate).
I think the 1947-55 optional rear side-lamps ("bullets") had glass lenses.
As posted above, the diameter of the 1954-1955st and 1955nd pickup tail-lamp lens was different from the 1956 and later pickup tail-lamp lens diameter. But, I might be miss-reading the Master Parts Catalog regarding both the 1st and 2nd series 1955 having the same size lens as the 1954 lens?
