Actually it was the Ati Radeon 9500 non pro that could be modded into a Radeon 9700. Regarding the ATI Radeon 9600, there was a variant called Radeon 9550 that could be overclocked from 250 mhz to 400 mhz.
Sometimes. At least some of those 9500s were binned parts that showed their broken bits when you modded them. I had one. The screen turned into a kaleidoscope when I tried to play a game.
Was definitely worth a try if you had one though!