That doesn't make sense since our phones are already registered with our old phone numbers. They can't just ship us a random phone with the same specs. It has to be the specific phone because it's already been provisioned to activate on our existing phone numbers, assuming it's an upgrade rather than a first-time iPhone.
Not to mention, I've already received an email with my AppleCare+ Proof of Coverage which lists the specific device Serial #. There is no way they can just randomly grab devices off whatever shipment is close. That would throw a huge monkey wrench into the works of the provisioning and AppleCare+ systems.