When I pre-ordered the Shack told me that they will call everyone on June 3 the day before and then he made the appointment.
I called back to the store yesterday, and the manager told me the samething. They are not opening at 6am, but will start calling people on June 3rd. But if we pre-ordered, we can pickup in the morning around 8:30am.
Maybe they don't have more than 4 pre-ordered at the store..