I know, I know, the first question would be, what are you crazy?! But I was curious if I was to order a Verizon iPhone 4S, would it actually work on the AT&T network if I put an AT&T sim card into it? I guess I'm just a little confused on if there are separate versions of the phone like there was when the Verizon iPhone 4 was released. I'm under the impression that the 4S is just a single device. Thanks!