Though the FCC documents appeared to show that there was a physical difference in size, this will not be the case. And the new device will continue to operate in the same manner. There were some other details that we uncovered that do align with the fact that Apple says component changes have been made. Namely the fact that this mid-season refresh, designated as an Apple TV 3,2 in the firmware, will utilize Apple’s A5x processor and a Broadcom BCM4334 wireless chip.
It's thought that perhaps the size discrepancy was due to the device being measured with its external shell off.
Apple confirmed to the site that internal changes which don't affect product features have been made to the device.
“We sometimes make component changes which require an updated model number for regulatory approval,” an Apple spokesperson told TNW. “The component changes we made don’t affect product features and Apple TV customers will continue to have the same great user experience.”