Most people do not know but Samsung is selling two versions of the Galaxy Note 2. One is N7100 and second is N7105. The N7100 is the international version with no LTE connectivity built in. This one will not work with the ATT bands.
On the other hand, the Note 2 N7105 has LTE (700MHz (Band 17) / 2100MHz (Band 7)) and if you are in America, we really suggest getting the local version. Other than that, the specifications of N7100 and N7105 are same both internally and externally.