I am on tmobile and currently have an unlocked 4s. I know apple updated the GSM phone in April after tmobile came on board so that the 5 would take advantage of all the Tmo bands (I think the 1700 band was the one that was added?) So I'm trying to get a 5 on ebay but have to avoid the ones that are pre-april. According to wikipedia (a source I generally avoid at all costs!) the april model for BOTH tmo and at&t supports 1700. My question is: if I get an At&t model, from after april, (last 4 of serial #Fh1d), I will be able to unlock it and be good to go with all tmo has to offer? Basically the at&t and tmobile models are exactly the same right? The only difference being that each is locked to its respective network? thanks!