Chevrolet Silverado rendering ... As such, we have OOBS (old-old body style, for machines built before the late 80s), OBS (Old Body Style, which covers units that came between the late 80s ...

Chevrolet trucks were built on the C/K GMT400 body style (some sources include trucks through 1999, while others say 2000 or even 2002). Now, they're known colloquially as "OBS" trucks ...