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 WarningEmergency
With Automatic Crash Response, the built-in system can automatically connect
to help in most crashes, even if help cannot be requested.
Press to connect to an Emergency
Advisor. GPS technology is used to identify the vehicle location and can provide
critical information to emergency personne ...
Moveable Window Schematics
Defogger Schematics
Window System Component Views
Window Systems Component Views
...
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 ...