Questions/Doubts Re: 1966 273 Commando Intake Manifold

The hole with the plug I'm talking about doesn't go into the intake section. It doesn't go anywhere......it's just a threaded hole with extra casting around it. I doesn't mount anything either. Look at post #3. That's the manifold I'm talking about.

This one sold here on For A bodies only in Feb. 2018. It has the triangle thing and the cast in boss, but no threaded hole. ????

273 intake with cap.jpeg