I ordered a chrome mirror cover off the web and the original manufacturer was PUTCO. Many websites offer this same cover. If you are interested be careful. The cover does not go around the entire mirror like you get from the factory. It looks OK until you’re sitting inside. The inside of the mirror is not covered. The photo explains the situation:

CHEAP BLING, HUH???

RYD

Just say no to "Bling"

You can buy original gm chrome mirror housings for much less than a lot of chrome stick ons.

Prefer OEM bling when available