There is a guy on the JTV forum who has swapped his tuners for Planet Waves locking tuners without trouble, here is the thread:
Maybe this helps,
I am pretty sure all of the Korean JTV guitars now come with locking tuners.
If you look here: http://tylervariax.com/guitars.php
1. Click the "JTV-89" red button
2. Then click the "Specifications" tab and you will see:
- Sealed tuners (16:1 turn ratio)
I was just wondering if the mounting points match up with any standard sets of Hipshot or Sperzel tuners... spoiled by locking ones on all my electrics and not having it on my jtv89 Korean is gonna bug me...
Sealed tuners does not mean locking tuners, it means the gears are not exposed. The tuners on the JTV89 are not locking.
Yes, you need 6 in line left handed tuners. Sometimes it is called treble side only. As far as mounting holes you have to get someone to post a pic of the back of the headstock and compare to what you want to use.