I'm on day 9 of ownership and still have not received an update, so the theory that Tesla waits until after the return period to send updates is out. I sent in a service ticket a few days ago, and received this response yesterday:
"Hello Evan,
I would be happy to help with your inquiry about software updates! I have reviewed the data for your car's software and have found no errors. We release software updates in batches so that we can thoroughly test each update with every configuration of car, and often release new updates slowly over time.
Once your car has an available update, a notification will display on your touchscreen to install. In general, connecting your car to a strong WiFi signal as much as possible will help avoid any possible delays in receiving updates.
Please let us know if there is anything else we can do to assist you in any way, and thank you for being part of the Tesla community!"
So looks like I will need to keep waiting.