'67, definitely. I've had three '67 Chevys, one '67 GMC, and one '67 GMC Suburban. All of these but one were big back window trucks and not re-cabbed. In 1968, ALL cars and trucks sold new in the US had to have sidemarkers. Yacht, I disagree on the back window being a Federal requirement, I've got a '69 Dodge D100 parts truck w/small back window. I've looked thru the Federal Motor Vehicle Safety Standard list and don't see anything about the size of the rear cab window mentioned anywhere.
