I agree, it seems unlikely they could produce any significant number of cars AND get them through PDI that quickly. So maybe a good number of those cars are already built and going through PDI now? But then why not hand out VINs on many of them? Only a few here have been told a VIN is coming soon so far. Given you need the VIN to apply for financing and set up insurance, you'd think they would not want to create an unnecessary bottleneck there.
How much would it suck to have a car ready before the 31st of December, but you can't pick it up because of a snag at the bank or insurance company? It's not like those employees are immune to the holiday vacation schedule, either.