That's interesting (and questionable). On the tracking timeline, 'Final Prep' is after shipped. A friend had hers switch from shipped to 'Final Prep' earlier this week. The dealership called to say it had arrived.
Edited to add: Final Prep has replaced Delivery. It's just a new heading that...
'Final Preparation' means it's at the dealership (ie, it's been delivered). The dealership typically needs a day to do whatever it is they do before releasing the vehicle.