Wrong sir, this is IN FACT a 1988. The GMT400 body style trucks first debuted for the 1988 model year, but only for the regular and extended cab pickups. While the crew cab heavy duty trucks and the Suburban's, Jimmy's and Blazer's still used the square body style.
1988 was the first year for the extended cab on Chev & GMC fullsize pickups. Rewind to 1983, extended cabs were first introduced on the smaller S-10 & S-15 pickups.
Those generation Chevrolet & GMC fullsize pickups with the dual glass headlights were produced from 1988 - 1989. In 1990, long plastic rectangular headlights replaced the dual glass ones.
@@johncleveland3015 Actually GM continued this body style until 2002 for the C3500HD (Cab & Chassis). The only difference was a filler panel between the grill and front bumper because the truck's frame was so beefy. I have a 2000 GMC C3500HD.
1988 was the first year for that body design & those are OBSs. The square bodies were the last body design right before those OBSs. Only the plain cab pickups were redesigned to that OBS style in 1988 & not to forget they were the first to come in optional extended cab models too in that year. The crew cab pickup & SUV models on the other hand still had the previous square body design up through 1991.