If you're using fresh valve cover gaskets you shouldn't need to use RTV in addition. You WILL need to put a dab under the half moon and on the seams between the half moon and the head.

Besides the moon(s), you'll also need the outer valve cover gasket and both spark plug hole gaskets. I suggest p[utting a dab of RTV around the cam caps and just a tiny bit in the groove in the valve coverto make sure the rubber guy stays in place as you put it on.

Before you go through all that business, make sure it's not your power steering pump leaking on to the block and trickling down.