In what fleet did the alternate USS Iowa serve?

Uh, newest SNW episode spoilers I guess.

In "Tomorrow and Tomorrow and Tomorrow" we are introduced to James Kirk, captain of the UEF Enterprise. This prefix is visible on the dedication plaque when La'an arrives on the bridge.

Curiously, later in the episode when La'an asks Kirk where he was born he says the USS Iowa.

What gives? Was the Iowa was a cargo ship? Maybe in this timeline, "USS" stands for "United Shipping Service." Or perhaps at some point, UEF ships did use the prefix and they changed it because the wanted "Earth" more clearly in the identifier.

What do you think?