Oklahoma is one of the states Tesla cant sell cars to. They get around this by selling you the car in California, and then delivering it to you in OK. This means, however, you wont be rejecting a car you dont like, because in practical terms, you own the car once it leaves CA.
This is why you have to pay for it in advance. This is different than people in states where Tesla is allowed to sell.
Unless something has changed for people in these states where tesla cant sell regarding "accept / reject", you should expect that you own the car when it shows up in your driveway.
I dont work for Tesla or anything though, I have just been here a while and remember how this goes for people in the few states that dont allow Manufacturer direct car sales.