The truck data books for 1950 and 1954 show pictures of RPO 249 (available on panel body trucks). They describe two bullet tail lights for panel truck bodies (for both panel-type doors and end-gates in 1950 and 1954).
There were a few other accessory tail light kits (at least in 1954), including bullet-style lights, that a dealer or owner might have installed on any body.
