So is that chip carbon build up or metal damage? And considering how much work you've gone thru to get that valve out in the first place, it would make sense to be a thorough as possible and so you don't have to go through this for the rest of the life of the car. So as brand new as you can make that head before you put it back on the better...
Replace it. Your peace of mind will be worth the price. Otherwise, you will keep thinking of that valve as long as you have the car.
IF you have gone to ALL the trouble to get it apart that far........I would suggest a complete rebuild: Pistons, rings, valves, seats, bearings......the whole 9 yards regardless of how the individual parts LOOK.
