2014 was the year that GM did a complete body change on the Silverado and Sierra 1500 models. The 2500 and 3500 models changed to the new style the following year in 2015. On the Chevy side they did another front end change in 2016 but only on the 1500 series. The 2500 / 3500 Silverado's use different headlights right though from 2015 to the 2019 model year and the lights from the Silverado 1500 don't fit them. Same thing with the Sierra Heavy Duty models, they take different headlights from the 1500 series. GM continued with the design that the Silverado and Sierra use different tail lights and the Sierra Dually model still uses the Silverado tail lights. The SUV's all use a completely different head light and tail light design.