As far as I know, their are no "official" os6 for the Pearl 3G yet to have been released. If your interested in a Leaked OS 6.0.0.481 just don't expect much support much from carrier tech if you should start suffering from any issues, which you'll most likely face.
If & when os6 is released for the 9100 it should run fine on the 9105 being that they are both Pearl 3G's with different keyboards.