From experience messing with mine and looking at the parts diagram, I think that is a totally foreign part. The only thing between the airbox and the throttle body in the diagrams is the intake hose itself, and a metal clamp on each end. No gaskets.. the "seal" is the plastic pipe directly on the airbox and TB.
Stock intake system correct? Some snorkel systems could use parts like that as a gasket.. but if your truck had a dorkel you'd know. Plus, it should be on the other side of the air cleaner and charcoal filter in the airbox.
Stock intake system correct? Some snorkel systems could use parts like that as a gasket.. but if your truck had a dorkel you'd know. Plus, it should be on the other side of the air cleaner and charcoal filter in the airbox.