They definitely know. They collect your driving data even when auto pilot is off, so I'd imagine they collect everything when the autopilot is actually engaged.
Tesla specifically said that the information was in the car and wasn't transmitted to HQ, so they didn't know. If what you say is true, they're lying to the USG.
Let me share an example. I had an accident in a Model S, front-end, which didn't cause a loss of power. Tesla called me a couple of minutes later, saying that they knew I'd had an airbag-deploying accident, and asking if I needed an ambulance. From the description of this accident, power to the Tesla was lost before there was time to phone home.
