Yes, 10.2 legacy works great, even on the X300. I upgraded my old laptop last week via ISO and the upgrade installer got rid of the ATI driver and installed the generic SVGA driver instead. Once I reinstalled 10.2 legacy, all was good
I'm not sure, my card isn't listed for that driver. I'll stick with the older one, it's not like I'll be playing Crysis any time soon.