The brains in the plug-in download section are all for Hal 5.
Brains for Hal 6.0 - 6.2 are only available to the individual owner of Hal and as such, are not generally interchangeable nor sharable with others, meaning that you would need to be an owner of the program in order to have the brain in the first place.
Perhaps this is to what Bill was alluding.
You buy Hal, you develop his brain as you see fit not as someone else does.
There are numerous plug-ins to enable Hal with different abilities but they are only a small portion of Hal's larger brain.