You should remove the pulley to make sure the back side is not scored up. That will only tear up a new friction surface.
You can get to the parts lists herehttp://www.partstree.com/parts/
Type Toro in the 2nd box and the 31-14K802 model number in the 3rd box. Your local Toro dealer can order the parts if they don't have it.
A fresh smear of grease on the pto needle bearing before reassembly is a good idea. When you put everything back together leave the pto brake pad loose. Apply the pto so everything is tight and place a business card between the brake pad and the pulley. Hold the pad tight to the pulley as you tighten the bolts. Then remove the card. This gives the proper clearance. After a couple of pto clutch applications under load don't be surprised if you need to tighten the linkage to prevent clutch slippage. Don't want that to happen again. The pto handle should snap down with some authority.
One way to extend clutch life is to apply the clutch at 1/4 throttle before the deck is into the long grass. When the blades are up to speed increase the throttle to mowing speed.