Both these gaskets are deep in it. I always change #2. The cover gasket #3, if it is soft, no kinks or nicks, I clean all the old sealant off the corners and apply small dabs of RTV high temp O2 sensor okay stuff when it is clean and dry. But I change it every other time. Don't forget the little orings if you lift the cam bridge. Be sure to put bits of rag in the spark plug holes so you don't lose something down there. Also have to adjust I change the water pump shaft seal that is in the head. The mud guard for the water pump, every other time. Which, makes it not often as you usually don't have to change shims every time you check. Any rubber gasket that is not soft or is deformed is a gamble. Add the fact that it is hard to get to and that equals; use a new one.
Mount Vernon, WA.
tire guy, I'll mount your tires.