What under the plastic? (roof rails)

[jsbihn]

Hey all,
Its time to play, whats under the plastic.
Ok on the roof (which also goes down along the side of the truck where the tops of the doors are at) there is a black plastic that runs the whole length of the truck on both sides. It doesnt matter if you have a SUT, SUV, with roof rails or without... it is there.

OK, I am trying to find out if there is anything under that plastic... something solid you can drill into and bolt or screw into?

Thanks