The pulley in the pic is from the early 6.5 N/A serpentine setups. Do not, I repeat do not machine the back thinking it will work. The hole is conical and will weeble wobble on you if you do that "fix". yes I thought I was so smart at one point.
The part# you listed is correct for the newer serpentine set up and is really affordable, I have used it. The generator is not necessarily the difference in the line up, more so the generator bracket type used on the 6.5 engine you have. If turbo, for sure you need the 12460259 at least, but the best is to go to the clutch pulley which is kind of hard to find/expensive.
The fixed pulley can possibly make your belt screetch/noises and in worst cases as I have heard it can jump off coming down from high rpms due to the higher amp generators inertia. But it will work. I just recently found a clutch pulley and have only had it on for a bit, no screetch and much more confident I dont have to worry about a jumping belt.
