Yes your right, it does add up fast $ wise. I would be sure to get the old regulator back from the service dealer. If your doing this work because the rotor (magnet) came loose and tore up the stator, there is a good chance the old regulator is still good and it would be nice to have it as a spare down the road for testing purposes. The new parts they installed are not exchange rebuilt so you own the old ones.
Actually with labor,towing, primary gaskets, primary oil, stator, regulator, rotor, tax and a new battery, you did not do too bad. I would have guessed even more.
Hoop!