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 WarningInstallation Procedure
Clean and prepare the attaching surfaces for welding.
Position the roof rear header panel (1) on the vehicle.
Verify the fit of the panel.
Clamp the roof rear header panel into position.
Spot weld accordingly as noted from the original panel.
Apply the sealer ...
Battery
Refer to the replacement number on the original battery label when a new battery
is needed.
WARNING
Battery posts, terminals, and related accessories contain lead and lead compounds,
chemicals known to the State of California to cause cancer and reproductive harm.
Wash hands after handling.
...
Rear Side Door Upper Hinge and Lower Hinge Replacement
Preliminary Procedure
Remove the rear side door. Refer to Rear Side Door Replacement.
Rear Side Door Hinge Bolt (Qty: 4)
Caution: Refer to Fastener Caution in the Preface section.
Tighten
25 N·m (19 lb ft)
Reart Side Door Hinge
Procedure
Adjust rear side door as needed. Refer ...