[rzv500r]

The amber roof marker lamps #19156090 when ordered as an RPO accessory are installed at the dealer just as hummer guy mentioned and there doesn't seem to be a supply problem with them at all, they are readily available. There is however a redesigned exterior A pillar trim molding in the works that GM sent out a bulletin on months ago to deal with the wind noise caused by the original design fitting loosely with an excessive gap between it and the roof rail trim. This may be what your sales person is referring to and may simply not be completely knowledgable on as the two outer lamps that come with the roof clearence lamp kit actually get mounted to the A pillar trim but I can't see where anything like this would hold up production of a truck.