Did you just Google all the RPOs on your sticker, or did you actually pay for a VIN lookup from somewhere like compnine.com? The reason I ask is that most GM RPO codes have been recycled over the years in different vehicles, so they may mean different things depending on the application. A VIN lookup on compnine costs $5 but they provide a detailed breakdown of the RPOs that are accurate to your specific vehicle. If you really want to know exactly what the truck had when it rolled out of the factory that's what I'd recommend doing. They give you other cool info too like how many other trucks that year had specific RPOs, and exact production date of the truck.