I ordered inline. It did not ask if I was a current owner. My understanding is current owners get priority. How will they know I am a current owner?
I'd like to know as well. Just to be safe, I made sure that I used the same email, name, address, phone #, and even the same credit card for the deposit as when I bought my MS.
Using the same email address as your Model S/X/Roadster used in your 'MyTesla' account is how they tell you are an owner. Use the same email in your reservation.