Well, I talked to the dealer that I'm working with. He hasn't looked, but he seems pretty convinced that the 2005 FS650e bikes are equipped with 4.25" rear wheels.
The '05 owner's manual shows a 4.25" wheel for the FS-e bikes.
The '05 parts manual shows a 5" wheel for the FS-e bikes.
I've seen '05 FS-e bikes with OEM Pilot Sport tires, and I've seen them with OEM Pilot Power tires. We already know that the '06 comes with a 4.25" wheel and Pilot Power tires. Maybe there was a change mid-year.