I just noticed that in the 2016 M3 reveal, the M3 chassis already has holes for the AP2 cameras in the B pillars. In hindsight this makes perfect sense, as (IMO) Elon referred to AP2 (EAP/FSD) as the spaceship feature in reveal pt 2. It's interesting that the M3 prototypes at the reveal didn't have the AP2 cameras put in. I wonder if that was intentional by Tesla to hide the AP2 at that time.