Previous iPhones were shaped somewhat differently on different carriers. But to answer the question, all carriers have iPhones with the same form-factor now.
i almost picked one up a few days back at a Verizon store, but i second guessed it as the price was damn near 40bucks...im glad i did beacuse i got one for about 20 bucks a few days later...Its called a iPhone 5 Shell/Holster combo....for those asking and its "made" by Verizon, or aka an "original" product...not sure who the real manufacturer is tho.