Don't read too much into that and get your hopes up.
Best buy is accepting preorders, but that doesn't mean they are going to be receiving any special amount above and beyond what they were going to be getting. Consequentially, what will be happening is this:
You preorder the phone and your name gets added to the list.
Best buy starts calling people on the list when they receive their phones and scheduling an appointment with you to have your phone picked up. Once they run out of phones, that preorder list is meaningless. Everyone else on the list will have to wait until the next order.
So basically, if they get 10 phones in tomorrow, they will call 10 people on the list tomorrow and tell them their phone is in. Then they will set an appointment with you for Friday when you can come and get it.
The fact that they are calling you has nothing to do with when you can come get it. The date for that is still Friday. (or later if they run out of stock before your name is reached on the list.)
Sorry.