Earlier in the week we reported that, due to LTE fragmentation, Apple was forced to make three different versions of the iPhone 5. A CDMA handset, and two GSM models, one specifically for AT&T.

As it turns out, there’s something weird about the AT&T model. It’s been recently discovered, via leaked FCC documentation, that it supports LTE on two unlisted bands, cellular and PCS..

It’s ExtremeTech with the find:

“Officially, Apple states that it supports LTE band class 17 (lower 700MHz without A block) and LTE band class 4 (AWS-1, 1.7GHz/2.1GHz) for Release 9 LTE. However, the FCC documents for the device state that it also supports LTE band class 2 (PCS, 1.9GHz) and LTE band class 5 (Cellular 850, 850MHz) as well. That means that this device actually supports four LTE bands, not two.”

By itself, this might not look like anything. But GigaOM points out that AT&T has been openly shopping around for new bands to deploy LTE, since its current network will only take it so far.

And since it lost a lot of its AWS spectrum to T-Mobile when the acquisition deal went south last year — it was part of the break-up fee, it has two choices: buy new airspace, or refarm its own.

“It just submitted an enormously complex proposal to the FCC that would allow it to turn its now useless 2.3 GHz into a private LTE band. But with these new frequencies in the iPhone hint at another possibility: Ma Bell may be planning to cannibalize its 2G and 3G networks to gain more LTE capacity.”

Just as T-Mobile is refarming its network to be more iPhone-friendly, AT&T is asking the permission of the Federal Communications Commission to refarm its unusable 2.3 GHz spectrum into LTE.

All carriers will eventually have to do this to their networks as wireless tech evolves. But that’s not expected to happen for several years. So, again, it’s weird that the new iPhone is supporting it now.

Could AT&T really be planning a major network overhaul?