He must’ve found a ZL1 in Nitro Yellow, otherwise the only other yellow for the 6th gen were 2016-2018.
Here’s the PDF for the OEM splash guard install.
Front
https://www.chevypartspros.com/docs/...z11dSD5COtEu8E
Rear
https://www.chevypartspros.com/docs/...JucZzWCabsDuT4