RAW support is a bit confused and murky at the moment. Prior to the release of Aperture 2 it was based in the Operating System, and so an update worked for all apps that ran on that OS. However, this meant that it was taking very long for Aperture (and iPhoto) to support newer cameras. So now the RAW support is built-in to the applications. iPhoto 08 is geared to this, but v6 seems not to be. Therefore there it would require an update to the Operating System to add new cameras to v6. OS 10.4 has not been updated since 10.5 was released, and I wouldn't expect it to be. Therefore I would not expect new cameras to be added to v6.
This is what gives that impression I guess.
However, I'm not sure. As RAW support was part of the OS at the time of release of iPhoto 08, it may well still be there for it, with a different system in operation for Aperture, which certainly post dates 10.5 and iPhoto 08. So, the thing is, I'm really not sure.
Regards
TD