Probably built in Fremont. Same as it’s always been.
edit: Technically the (online) sale is in California. Car is shipped to Texas. That’s legal.
Sales from Giga Austin will be different.
This is what I've been saying all along. The legal aspect is regarding the paperwork, NOT the physical car.
The purchase of a Tesla in Texas is a business process, and makes no difference where the actual vehicle is located.
The transaction of the paperwork for the sale has to originate outside the state, or, more specifically,
a sales transaction cannot happen at a Tesla store in Texas. This has nothing to do with the physical car, only where the paperwork is handled.
For contrast, the dealerships (cartel members) in Texas will offer to process the registration on behalf of their customer, in fact, they are required by law to
offer this service.
The buyer does not have to accept this "service" and the dealers often do get confused about it. They think the law says they must actually process the registration for the customer. This is a convenient misunderstanding on their part.
Trying to convince an ICE dealer to let you register your own vehicle at the courthouse throws a wrench in their works, but it can be done. I've done it. By doing so, the buyer can avoid the onerous fees for providing this so-called service which the dealer IS required by law to OFFER, but is not required to perform. The customer is not required by law to let them do it. This statute was written in such a way to allow this misdirection to be sewn into the fabric by the dealership cartel, netting them additional income.
Whenever one is registering any vehicle in Texas that has been purchased out of state, the owner will always have to handle the registration themselves. It seems most people have little experience with this concept, but that is how the registration works. You go to the courthouse, fill out the forms, pay the fee, take home the plates and they mail you a title. You can also do this online and have the plates mailed to you.
The laws are specifically about the process for the paperwork for the sale. The car can be sitting at the factory in Texas, or at the service center in Texas, or anywhere in Texas really.
As long as the original manufacturer's certificate of origin is assigned to, say, a company in Fremont for example, and then the vehicle is sold to someone in Texas by that out of state entity, Bob's your uncle.
Some people seem to think there is some elaborate network of state agents that will track every car coming out of GigaTexas to make sure the physical car left the state before being sold to a Texas resident. Do these people actually believe that there is both budget and staff allocated for enforcing any such foolishness? That would be absurd.