Well, apparently gm, is bowing to Cali.. YES, I know this is old, wanted to clarify.. the laws previous posted do come into play...
Here's a couple of articles..Funny thing is... these articles were posted about the same time this topic was fresh..
https://gmauthority.com/blog/2020/09/no-roof-marker-lamps-on-chevy-silverado-hd-gmc-sierra-hd-in-california/
https://pickuptrucktalk.com/2020/09/california-drops-the-ban-hammer-on-gm-amber-marker-lights-you-wont-believe-why/