Showcased here is an unpainted Brainiac first shot. First shots, sometimes referred to as test shots, are used to test the steel molds prior to mass production. The color of the injection molded plastic was irrelevant since the figure served only test purposes. Typically nonproduction color first shots are more desireable to collectors.
This view reveals a lack of copyright info on the inner thigh. The copyright information and foot holes are typically etched into the steel production mold upon completion of its testing. However, the Brainiac shown here does exhibit foot holes, so the steel production mold was certainly tested again after the holes were added.
Above is a comparison with the fully painted production figure. I think the differences bewteen the two are quite evident. Notice that the silver on the left limbs lacks the blue tint found on the production figure. The torso is not sonic welded, but the internal mechanism is fully functional.