How can I tell if I'm on the "Official" or not?
Easiest way is to just check what version rom you are using. Unless you are using custom rom, it'll either be MLG for leaked version Kitkat or NC2 which is the official latest Kitkat. I think the OP was talking about the leaked version Kitkat which has the old (better) bootloader.
The latest NC2 has updated bootloader which make it impossible to downgrade or root.
If you are still on MLG and never updated your bootloader (by installing NC2), then you should be able to go back to MJ5 JellyBean. Everyone or most of us on official NC2 is stuck with this version and regretting taking the OTA update.