Factory Roof Rack

I have a set of factory equinox roof racks that I want to install on my new equinox.  Do I need to remove the cover at the back of each roof rack to do this?  If so, where can I buy the plastic rivits (or whatever they are) that hold the covers down at the back of the roof rack.
 
Thanks

I wold get the dealer to do it, case it leaks afterward it will still be warranty, most people I see do this screw up drilling a hole or something and it leaks and of course no warr cause you did it...and ya it gets bad from there