I just deciphered my entire sticker from the glove box.
Use these 2 sites, if the list site doesn't have a code then use the site with the search. Usually the option in all caps refers to the H2.
http://www.rpocodes.com/GM-RPO-codes...0through4.html
http://www.gm-trucks.com/rpo-code-lookup/
I'm happy to say I finally figured out mine is a Lux with the chrome package (which is mostly gone now lol).