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
Drill 8 mm (5/16 in) for plug welding along the edges of the front
compartment upper side rail as noted from the original panel.
Clean and prepare the attaching surfaces for welding.
Position the front compartment upper side rail on the vehicle.
Verify the fit of the fr ...
Roof Side Rail Inflatable Restraint Module Replacement
Warning: In order to prevent SIR deployment, personal injury, or
unnecessary SIR system repairs, do not strike the door or the
door pillar in the area of the side impact sensor (SIS). Turn OFF the ignition
and remove the key when performing service in the
area of the SIS.
Warning: When pe ...