I took delivery of a Model 3 at Colma, CA in the afternoon and I had to accept delivery before I had access to the interior (the app showed the car, but it asks to accept delivery to unlock it). I did go to delivery check-in to ask and they told me to do the same. All the documents and the key cards were already in the car, there was a FedEx envelope to FedEx the DMV documents to them. My car had a few minor scratches, which they told me to schedule a service appointment for in the app. However, I paid everything online and I guess I got set for a “contactless delivery” appointment.

It might be different for people with a check or maybe if you went before they had a chance to leave the documents and keycards in the car (so they would have to open the car for you anyways).