First of all, -currrent is the
testing branch, and should not be referred
to as "the official" in the sense that you seem to use it.
On the day that Slackware-13.0 is released, if you have updated everything
in Slackware -current, you will basically have the same thing. You can use
Alpha Geek's sligdo to change your -current to 13.0. This will essentially
change what you have into the Slackware-13.0 release.
When Slackware-13.0 is released, Pat and The Core Team will enjoy a time of
rest before working on new packages for the next testing, or -current, cycle.
If you want to run -current all the time, you should be doing so with either
an eye to help test new software, or play with a machine you can hose which
will not cause you to break out in sweats. So if you don't want to chance the
hosing of a system you rely upon for daily work, run the stable release and
not -current. If it does not matter that you might break something on your
system, or you want to help test the new software, run -current.