My team is trained not to pay for a mirror if there is any mark on it. I don't know about anyone else, but I find that the factory painted Grand Am mirrors don't break... just the unpainted dual post style.
We get ours from a local office of crosscanadaparts.com, for everyone in the US, lkqcorp.com is essentially the same company.
We install them ourselves. Always good for a laugh when a customer thinks you need to be a certified mechanic to change a mirror. lol