Not sure that this tells us anything - just another possibility. I struggle to see Apple moving TouchID to the back of the phone just to get rid of the bezel(s) on the front. That seems like a lost from vs. function battle to me. Yes, getting rid of the bezels looks nice (look no further than Samsung's new phone), but TouchID on the back will never be as viable as where it is now. Considering the critical role of TouchID when it comes to ApplePay and the work that Apple had to do to get banks and retailers onboard with it, I can't see them ditching it completely either.