hi, new to the forums and just bought my ipad2 32g wifi 3g from an ATT store here in the US. i chose this GSM version since i've read they're unlocked and i will be bringing this abroad every now and then and i wanted the option to use a local carrier abroad for 3g access. my question is why do i have the MD066LL/A model number on my ipad 2 while i see the other model number MC774LL/A more often in apple stores and other online stores? is there any difference? am i sure that my ipad 2 is unlocked? thanks!