There won't be any mistaking an iPhone 5 for an iPhone 4 or 4S. A lot has changed on the outside of the iPhone.
The most obvious alteration to the bottom of the phone is the exchange of the large 30-pin dock connector for the diminutive Lightning connector.
The headphone jack is now on the bottom of the iPhone, right next to the updated
speakermicrophone grille—a series of holes rather than a mesh-covered slot.
Other notable differences are the slate bezel, as opposed to the stainless steel that wrapped around the 4S, and the chamfered edges between the bezel and the front/rear cases.