I too saw that the top marker lamps are installed at the factory from the website, but then again that website hasn't been updated in awhile!
I was at the dealer last week, Hummer of Kansas City, and although they are generally clueless, they said that these add-ons are installed at the dealer. He even went so far to tell me how they installed it.
Just my $.02, but I think they are shafting you.
with your assessment.
Bill