Well, there are many ways to tell if it is legit, that's one way, another way is to take it into KV modder and see what happens.
And chances are, its probably banned too. But i wouldn't take any chances of giving it to your friend.
Well, i wouldn't use it, because it will be a pain in the *** doing it, it may be easy, but if that were me, I wouldn't do it.
Why? Because I'm lazy :)
No, chances are, it's not.
If you inject it, it will mess up your JTAG really badly.
And what a KV is, is a .bin file that will unban your Jtag for a fixed amount of time.
Once the JTAG goes online with the Kv, it will get flagged and M$ banning process will just take longer.