Apple recently made a statement which seems to indicate that all iPhones will be in rather short supply for those customers who walk in without a reservation. It also states that the iPhone 7 jet black models & iPhone 7 Plus models have sold out completely in the initial online ordering period. Those who want an iPhone in jet black will have to order it online & just wait.
Apple said: “Beginning Friday, limited quantities of iPhone 7 in silver, gold, rose gold, and black will be available for walk-in customers at Apple retail stores. During the online pre-order period, initial quantities of iPhone 7 Plus in all finishes and iPhone 7 in jet black sold out and will not be available for walk-in customers. Availability at partner locations for all finishes may vary and we recommend checking directly with them.”