NOTE: SILVERADO/SIERRA 1500 2019
2019 is a transition year for GM. They produced a new body style for the Chevy Silverado/GMC Sierra 1500, but they are also continuing the old (Classic) body style for the 2019 Silverado/Sierra 1500 for both the 5'7" (short) and 6'4" (standard) bed lengths. There is no body style update for the 2500 & 3500 GM trucks yet.
The 2019 Classic Silverado/Sierra 1500 takes a different DECKED system than the new body style 2019 Silverado/Sierra 1500.
The three most significant visual differences between the old (classic) and the new body style are the fenders, headlights and exhaust:
1). FENDERS: The Classic 2019 Silverado 1500 is boxy around the fenders. The new 2019 Silverado 1500 is "swoopy" around the fenders.
2). EXHAUST: The Classic 2019 Silverado 1500 has a regular exhaust. The new 2019 Silverado 1500 has a fully branded tailgate and incorporated split dual exhaust tips.
3). HEADLIGHTS: See images below.
