Yes, and they will agree to a delivery date. That will be after 10,000 people who CAN pick up there car have gotten theirs and there's no rush anymore. If you had to deliver 10,000 cars, how would you do it?
If someone else is unavailable to pickup their car, then theirs will be unassigned and if it matches your needs, may be reassigned to you.
As the cars start to arrive, I'm assuming that the will arrive at the delivery centers on car carrying trucks. Those about 6 cars, and if they are delivering 50 cars a day, that's 9 truck loads a day. Each and every day until they get the ship load delivered.
This isn't basic customer service. This isn't basic car delivery. This isn't basic buying cars. This is delivery of one of the most anticipated cars with the largest sales in history. Want a car delivered on the day you want, head to any other dealer. Sorry, not bad customer service, it's reality.
And expect your window would have probably gotten smaller, the closer you get to delivery.
Also, while the timeframe is pretty wide, there will be a LOT of people who can pick the car up. With the US Model 3 push, there were a lot of people out of the country during the time, they just fell back in line.