04-05 use the KTS-RN12 where the 06 uses the KTS-RN12A.
The piece you are looking for is officially called a slider.
Sadly, these have all be DC'ed from Gilles Tooling for some time now (I think going on 3 years now).
They can not get these any more, I have tried.
Unless you find someone looking to sell a set just for parts you guys are going to have a heck of a time finding these. Gilles Tooling released a new axle block that will work but it is no where near as nice as the KTS style adjusters.