It's a good idea to have a valve cover gasket kit around just in case you do. The Viton® gasket becomes brittle over time from the heat and petroleum exposure, and eventually it won't be reusable. But if you're not leaking oil now, and there aren't a ton of miles on the car, you can usually clean it up and reuse it without any problems. Just put black silicone on any corner or seam in the seal when you re-install it.

The valve cover gasket kit will come with new sparkplug o-rings, and valve cover fastener grommets. They're usually pretty cheap, and if you're going through all the trouble of polishing a valve cover, a new gasket might well be in order.

If your valve cover is coated with one of Honda's lovely black or red finishes, you're going to hate stripping it, but it can be done. You're better off buying a bare one from eBaY and polishing that one instead. For instance... my CX's valve cover was black... a '93 non-VTEC Del Sol's valve cover is bare aluminum. I bought it for $10.50, and polished it while keeping the car in service. It took me a week to finish it, and 2 days to polish it.