I also received this same information twice in person and once in email:
First, when I ordered my white/white/19" on Oct. 12th and again when I went to my showroom this past Friday and heard it from another SA:
The Freemont Factory is still (at this moment!) making right-sided drivers and won't return to making left-sided until (he thought mid?) November. He also confirmed what the previous SA stated: that I should receive a VIN by the end of December.
I also emailed my delivery specialist and she stated "end of December but, there are no promises".
In April, Freemont was producing up to 6,000 Model 3s per week and Tesla completed 97,000+ deliveries in Quarter 3.
So is there time enough to produce and DELIVER to all of us with outstanding orders in North America before 12/31 to meet our tax credit deadline? I believe delivery is required to earn the credit.
That being said, Tesla's decision to announce that cancelations will prohibit identical builds for up to a year only makes me believe that they expect (at least the thought of) cancellations from this point forward - but is it because 1.) they expect people may cancel BEFORE the end of the year out of anger/fear of missing the tax credit as the deadline approaches (Q4 2019) or 2.) because Tesla already knows that they will miss the deadline and expect orders to be cancelled in response (Q1 2020)?
Either way, cancellations may occur - so why does it matter which Quarter?
With that deterrent to cancellation in place, there seems to be no harm in confirming if they already know our cars will be late unless it's all about the fiscal/numbers.
I will hang in regardless - can.not.wait!