Mobile carriers reportedly are testing 4G versions of Apple’s smartphone. But before you get all excited, it may not necessarily be the iPhone 5.

BGR says iPhone carriers are testing models with 4G LTE capability. It discovered evidence of a property list file (.plist) within the firmware, which definitively revealed Apple is developing the technology. Whether it’s for the next generation iPhone, or a generation after that, is yet to be seen.

As we get closer to the anticipated announcement of the next-gen iPhone, rumors are flying. After missing its traditional June launch, rumors pegged the announcement for September. That’s recently been debunked by some in favor of an announcement in October. Whenever it appears, the the iPhone 5 is expected to sport an A5 processor, 8-megapixel camera sensor, “curved” cover glass and a flat metal back.

The Guardian previously reported carriers have been testing iPhone 5 models inside “specially constructed boxes,” with hardware encased in “a dummy body.” This makes it seem it could be the iPhone 5 that is being tested for 4G support.

It looks like Apple is putting in a lot more time testing its next gen iPhone in the wild than it did with its predecessor in order to avoid something like last year’s Antennagate fiasco — which really, in the scheme of things, was not that big of a deal.

Or maybe employees just aren’t being quite as scrupulous about Apple’s closely guarded secrets as they have been in the past.

Photo: Steve Jobs with the iPhone 4 at WWDC 2010. (Jon Snyder/Wired.com)