The Lex Luthor action figure prototype showcased in this entry is referred to as an unpainted first shot. First shots serve as early samples sent back to Kenner from the overseas factories that manufacture the actual toys. Early tests of the production tooling (molds) ensure manufacturing specs are met prior to the onset of full production, so first shots and later samples are critical to make sure the final product ships as intended. At this stage, the functionality of the tooling is the priority, so the plastic color is inconsequential. This explains the interesting color combination exhibited by this first shot.
The above photo shows the absence of copyright information on the inner though. A mold maker etches this information into the steel tooling later in the process, so early samples often lack copyright information.
The final photo shows the absence of foot holes found on the production figure.
I've been fortunate to assemble a nice grouping of prototypes showing various pre-production phases for the Lex Luthor action figure, packaging, and even the mini-comic, many of which are showcased on my website: