Did 1992 Chevrolet 1500 come with a third brake light?

No, the 1992 Chevrolet C1500 did not come standard with a third brake light (high-mounted stop lamp). Third brake lights became more common in the early to mid 1990s, but were not mandated in all vehicles until later. While some 1992 C1500s *might* have had them added as an aftermarket accessory, it wasn't a factory-standard feature.