They are the same thing. By that time Tesla should be producing 500+ cars per week if they are going to hit the 30k/year pace that was quoted in the last conference call. At that rate they would chew through 1800 cars in just over 3 weeks so "Nov/Dec" is accurate for both of you.
For context, in Elon's most recent interview his expectation was that they would build 80 cars this week, after building 40 last week. If they keep doubling according to the ramp schedule they'll be producing 500+ cars per week by around the first week of October. By early to mid October all of the Sigs should be built and regular production will start.
P2009 should come out by mid to late November and P3853 should be complete by early December, with the possibility of being done very late in November if Tesla gets ahead of the curve. Everyone has gotten used to all of the delays we had in July and early August, but we are now deep into the ramp up, with only a couple of weeks of doubling left.
Looking backwards, we can see that if there were 80 cars this week, 40 last week and (probably) 20 the week before, that accounts for 140 cars so far this month. At the end of August Tesla had completed ~100 cars, so that gives us ~240 by the end of this week, which tracks very nicely with what we know about VIN's.
Continued doubling will give us ~160 next week and ~320 in the last week of September which would mean ~720 units produced through Q3, though deliveries to customers will likely only be ~250-400 by that point. Maybe they can even hit 500 deliveries if they have enough West Coast Sigs that they can deliver quick enough. It's hard to tell based on the notifications we've seen so far, but 500 seems at least possible if not likely.
Anyways, this is why so many Sigs are getting October notifications in the last week. The rest of the Sigs should be completed within 3-4 weeks, which means the rest of the notifications (with a 30 day notice) will be happening in the next couple of weeks once you account for 2 weeks for final shipment and prep (i.e. for a car coming off the assembly line on Oct 15 the owner will be notified by the end of September for a late October delivery). My guess is that the bulk of the notifications are apt to come in the next week or so for Sigs and we'll start to see notifications for regular P numbers in the week after that.
