There is no Air Bag fuse, power is fed directly from the IGN fuse. This truck does not have Roll Sensing Curtain Air Bags, so no switch is needed for those. The switch in the dash that takes a key is for the front passenger seat, it's set to Auto if bucket seats, or Off with bench seat. With all the trouble GM is in right now, disabling air bags is something manufacturers are going to really shy away from.
I would say the easiest way to disable the driver's inflator specifically would be to pull the 2 steering column cover screws, drop the lower cover, and disconnect the yellow connector to the spiral cable. The light will come on, but will go out once it's plugged back in and the ignition cycled.
HTH