Ok, so yesterday I was playing around with packets (finally found the encryption).
and I just tested random things.. turned a junk character from a Bard to a Katar:
at first I thought it was clientsided, obviously. but then I relogged and it's still there.
haha, I'm not even sure how it happened.
Anyways, so it seems like AK is not so exploit-proof after all, after doing this (BY MISTAKE!) a dupe exploit doesn't seem so impossible.
I
might work on a user-friendly packet editor when I have some extra time.
Edit:
If anyone was wondering:
yes, I can still use the harp for basic attacks.
no, I can't use Katar skills with the harp.
I assume that if I unequip the harp I won't be able to equip it again so I'm keeping it on forever :P