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
Cut the front hinge pillar body in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed
to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint.
Create a 50 mm (2 in) backing plate from the unused portion of ...
Tracing Powder or Chalk Test
Clean the weatherstrips and the contact surfaces with cleaning solvent.
Apply powder or chalk in an unbroken line to the contact surface of the
weatherstrip surrounding the perimeter of the suspected
areas.
Close the panel completely without slamming the panel. Closing the panel
comple ...
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.
...