Rumors of a successor to the dual sliding, Helio Ocean styling, At&t smartphone have surfaced onto the Internet thanks to the latest At&t FCC filing (or so we think).  Apparently a device labeled as the Pantech C280 has just gone through the rounds over at the FCC website and it includes the two frequencies necessary for At&t operation: WCDMA 850/1900 MHz.  Since these two frequencies are usually a shoe-in for an At&t device and the images included in the filing look exactly like a Pantech Duo, we are going to label this guy the Pantech Duo 2 until told otherwise.  While the FCC filing is interesting, the documents give little information on the device specs other than the frequencies so we are puzzled as to whether this will be the Windows Mobile 6.1 version with an upgraded camera or simply a low-end version to attract an even younger market.  Personally I think this will be the upgrade since downgrading the specs on the existing Pantech Duo would simply deliver a device with mediocre performance and a dream that a innovative form factor could be enough to win over retail sales.