Yes.
I called Apple and they said I'll be able to use the upgrade phone # in the store (IF I make it that far) and then later cancel the July 14th order. They said the upgrade isn't "used" until the phone is shipped, even though I've already paid the discounted price by pre-ordering for July 14th.
So I'll go try and get in line, and if I make it I'll buy the iPhone for another $300 and then cancel the July 14th order and get a refund.