Yeah it is what I do here so I deal with it every day. The info to the tow co. would be limited, I thought about it a little more and if they are a contractor for the PD they could get the phone # from the CHP 180 form if the officer happened to write it on there when he was working on the recovery. Still the tow company has no responsibility to call anyone, that would have been the officers job, he would have also mailed a half copy of the CHP 180 to the R.O.'s address. The tow company would have notified the R.O. too but only through DMV records and by certified mailing.
Then again these departments are always trying to shift the responsibility of different aspects to others to save money, we do most of the paperwork for them now and they just mail it out since it is still their responsibility by law. Just recently we were informed that we are now going to take care of scofflaw vehicles and the fines, there are going to be a lot of pissed off people in L.A. over that one.