The rules in Calif are a little odd. We are South Dakota residents and bought a rig in Calif. We had to take delivery out of state, also. If you buy a vehicle in Calif and take delivery in Calif, you have to pay Calif sales tax regardless of where you are going to register it. Most dealers know this and work with it all the time.
Did you buy from a private party? That might be why you don't have the original docs. It does take time to get the pink slip from the state.
Bill & Treasa Our Blog
2005 Winnebago Vectra 40AD
400 Cummins, Freightliner chassis
2004 Suzuki Grand Vitara 4X4