Intake manifold rings don't actually seal vacuum- - - - -the gasket does that. However, it's almost guaranteed you'll gat a vacuum leak from gasket misalignment if you don't use the rings to keep the manifold aligned with the ports. Yes, 216's had rings from the factory.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!