For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling and Enabling.
Disconnect the negative battery cable. Refer to Battery N ...
Installation Procedure
Align the body side outer panel reinforcement.
Drill 8 mm (5/16 in) for plug welding along the edges of the body side
outer panel reinforcement as noted from the original panel.
Clean and prepare the attaching surfaces
for welding.
Position the body side outer pa ...
Inflatable Restraint Roof Rail Modules
The roof rail modules are located under the headliner extending from the
front windshield pillar to the rear window pillar. The roof rail
modules contain a housing, inflatable air bag, initiating device, and a canister
of gas generating material. The initiator is part of the roof
rail module d ...