The spark plug well gasket is "built into" the valve cover, there is a non-removable portion of the valve cover that retains the gasket and it's technically not replaceable.

HOWEVER! They do sell the gaskets now, in order to remove and install the new ones you need to secure the valve cover in a drill press (or build a jig) and use a hole saw to remove material so the gasket can be removed. There is a metal spring ring inside the gasket so it's not as simple as "pry out the old one, pop in a new one" but it can be done, google search for it.

Most folks just opt to buy new valve covers though.

 

Yeah body you are awesome, thanks one more time for you help, are you an infiniti engineer lol, very good, answer, I think I will buy the new valve cover, well the 2