I do agree with you on this. The hardware for AWS in the GSM variant already, but I don't think Apple has issued firmware updates for iPhones before, and won't make an exception this time around.
I was also talking to a guy with a Mexican carrier iphone user that tried messing with the carrier config files and even though that band was supported on his iphone his carrier didn't push out a config file out yet to enable LTE usage. His results weren't that great with altering the ipcc files but when the official carrier settings were pushed by his provider and phone was restored it functioned as it should.
bad choice, I did that with an unsupported carrier it worked fine it picked up LTE but the signal was erratic, sent calls to voicemail, didn't reconnect back to LTE after a call etc etc.. after a few weeks apple released the approved original update for LTE in my country, I unistalled commcenterpatch and the hacked file and installed the original and it behaved the same way, also I recommend switching off the LTE switch because it might cause 3G timeout issues, it happened to me when i did the hack
After a restore the phone picked up original file and never had any issue at all on LTE it connects back and reconnects back instantly switching to 3G for calls/coverage etc.
which sucks because a fresh restore will make you lose your jailbreak,