do the hack creators ever come back here and update the version in the original post, so that we know if the hack has been upgraded to the current vBulletin version?
the most recent one I see is 3.5.2

Well, it's very, very rare that a hack stops functioning after a small version upgrade.

The reason why you see only 3.5.2 version is because that is the latest version added to the system. LiveWire is quite a busy man, so he tends to forget to update this sometimes (I used to do it for him back in the days :p). Things will be going a lot smoother though when the site gets upgraded to 3.5.x ;).