Would you use this pressure plate?
 

http://farm5.static.flickr.com/4024/...b486bc17e1.jpg

Disc looks pretty good. Plate is smooth, but you see the funky discoloration. The flywheel was the same, but is getting turned at the machine shop. Machinist can't cut the pp, I guess because it's sprung. It's an ACT. Never slipped (while I had it), never chattered. Thoughts?

I'd take some emery paper too it but so long as it's smooth/true (not warped) and never gave you any problems before, I don't see any reason to throw it out.

I'd put the emery paper on a flat surface like a piece of glass or preferably a surface table to lap the surface clean. If doing it by hand you run the risk of producing an undulating surface. Dunno how much material you would have to remove to make the thing look new or if the slight undulations would make that much of a difference but that's how I'd do it just for piece of mind.