If you have spent any time in Chevy and GMC truck groups or parts listings, you have run into OBS, NBS and NNBS. Nobody defines them, everybody assumes you know, and ordering the wrong part is easy when three letters separate two generations.
Here is the short version, then how to identify your own truck.
The quick answer
- OBS — Old Body Style, GMT400, 1988-1998
- NBS — New Body Style, GMT800, 1999-2006 plus 2007 "Classic"
- NNBS — New New Body Style, GMT900, 2007-2013
| Name | Years | Platform |
|---|---|---|
| OBS | 1988-1998 | GMT400 |
| NBS | 1999-2006 | GMT800 |
| NNBS | 2007-2013 | GMT900 |
The names are relative, which is why they confuse people. Owners coined them as each generation arrived, not GM. "New body style" has been thirty years old for a while now.
OBS: 1988-1998 (GMT400)
The GMT400 C/K trucks replaced the squarebody in 1988. Rounded body lines, that instantly recognizable dash, and the generation that has become the darling of the current truck scene.
Models: Chevy C/K 1500, 2500 and 3500, GMC Sierra C/K, plus Tahoe, Yukon and Suburban.
One wrinkle: light-duty GMT400 pickups ran through 1998, but heavy-duty GMT400 pickups and the GMT400 SUVs stayed in production until 2000 alongside the new trucks, according to Wikipedia's account of the first-generation Silverado. So a 1999 or 2000 3500 crew cab can still be an OBS body. Same overlap on SUVs — the 1995-1999 Tahoe is GMT400, and 2000 moved to the new platform.
One more note: Ford owners use OBS for the 1992-1997 F-150, so make sure everyone in a general truck group is talking about the same brand.
Shop OBS billet parts for 1988-1998 C/K trucks
NBS: 1999-2006 (GMT800)
1999 brought the Silverado name and the GMT800 platform — a clean-sheet redesign with hydroformed frame rails and the LS-based Vortec V8 family.
Pickups ran 1999 through 2006, and most full-size SUVs ran 2000 through 2006, as GMT Central's platform overview lays out. The Avalanche arrived in 2002.
This generation has been climbing fast in the aftermarket, roughly the way OBS did a decade ago. Clean, cheap, plentiful, and the interiors are old enough now that the plastic is cracking and fading — which is why the billet replacement market for these trucks has taken off.
One fitment trap inside the generation: 1999-2002 trucks use a different HVAC control layout than 2003-2006. If you are buying climate control knobs, that split matters more than the NBS label does.
Shop NBS billet parts for 1999-2006 Silverado and Sierra
NNBS: 2007-2013 (GMT900)
The GMT900 Silverado and Sierra launched for 2007 with new sheet metal, a new frame and a completely redesigned interior, and stayed in production through 2013 before the K2XX trucks replaced them, per Drive Sense's GMT900 generation overview. Owners called it the new new body style because NBS was already taken.
Shop NNBS billet parts for 2007-2013 Silverado and Sierra
The 2007 problem: Classic vs new body style
2007 is the most common reason people order the wrong part. GM sold two different trucks that year. The carryover GMT800 truck was badged Classic, and the redesigned GMT900 truck sold alongside it.
A 2007 Classic takes NBS parts. A 2007 non-Classic takes NNBS parts.
Three ways to tell them apart without crawling under the truck:
- The tailgate. The new body style has a large Chevrolet bowtie centered on the tailgate. The Classic does not, as etrailer's comparison describes.
- The rear turn signals. Classic trucks have amber rear turn signal lenses. The new body style does not.
- The badge. Classic trucks wear a "Classic" script badge, usually on the front fender or grille.
Trucks built in the first half of the 2007 model year are almost certainly Classics, but build dates overlapped, so check the tailgate rather than trusting the calendar. When in doubt, send us your VIN and we will confirm the generation before you order.
What about everything older?
- Squarebody, 1973-1987 — the flat, boxy C/K trucks right before OBS. Blazer and Suburban variants ran later.
- Action Line, 1967-1972 — often just called the C10 or "the '67-72," the generation that ends in the '72 everyone wants.
Which parts actually cross over?
Mostly, they do not. Interior billet parts are the clearest case: dash bezels, HVAC knobs, door handles and shift levers are cut to the specific dash and door architecture of one generation. An OBS door handle will not go into an NBS truck no matter how similar they look in photos.
A few categories are more forgiving. Universal-fit items like some pedal sets, radiator caps and dress-up hardware cross generations. Bed stake pocket covers depend on bed style more than generation. Treat anything electrical or trim-mounted as generation-specific until the fitment notes say otherwise.
Everything we make is machined from solid billet aluminum in the United States and built to the factory mounting points, so parts install with hand tools and no fabrication — but only if you order for the right generation.
Browse all billet interior parts
Frequently asked questions
What does NBS mean for trucks?
NBS stands for New Body Style. For Chevy and GMC full-size trucks it means the GMT800 generation: 1999-2006 Silverado and Sierra, plus the 2007 Classic carryover trucks and the 2000-2006 Tahoe, Yukon, Suburban and Avalanche.
What years are NBS Chevy trucks?
1999 through 2006 for pickups, plus 2007 Classic models. Full-size SUVs on the same platform ran 2000 through 2006.
What is the difference between NBS and NNBS?
NBS is the 1999-2006 GMT800 generation. NNBS, or New New Body Style, is the 2007-2013 GMT900 generation that replaced it. They share almost no interior or body parts.
Is a 2007 Silverado NBS or NNBS?
Both were sold in 2007. The Classic is NBS and takes NBS parts. The redesigned 2007 truck is NNBS. Check the tailgate — the new body style has a large centered bowtie and the Classic has amber rear turn signal lenses.
What years are OBS Chevy trucks?
1988 through 1998 for light-duty C/K pickups. Heavy-duty GMT400 pickups and the GMT400 SUVs continued into 1999 and 2000, so some later trucks still carry the OBS body.