The Tab 3 10.1 with LTE has already been released internationally as the P5220, running Jellybean.
If you want KitKat on it, you have to buy that and wait for the Samsung update. As always, updates come later on OEM brands. Considering not even Nexus devices have KitKat yet apart from the Nexus 5. (Although I think it has been released for the Nexus 7?).
OEMs like Samsung typically update their devices to the next Android version a few months after Nexus devices usually, 3-4 months.
So basically, no, there will not be a Tab 3 10.1 LTE with KitKat released. You will buy the Tab 3 LTE and wait for an update from Samsung to get it running with KitKat. A few weeks after such an update is released, the Tab 3 may come with KitKat out of the box, but generally you have to update it manually via Samsung Kies after buying.