The Tailgate Mirror fits on all Silverado's up to 2018. It does not fit the 2019 SIlverado nor the 2019 Colorado. The coming bracket system will work on the latest Chevy trucks.
Tailgate Mirror installed on 2017 Silverado 2500
This is with the tailgate up for easier viewing (also easier to install)
Tailgate Mirror installed on 2018 Colorado with screen view
Below shows with and without the Tailgate Mirror on an F150. It will look very similar on the Chevy