Ive seen those cups that go in the manifolds under the choke listed NOS on eBay a few times over the past year or so .. I'm not actually looking as my /6 Is newer but that's probably why I've seen them
Oops…careful, you are about to cause yourself unnecessary hardship. Those gaskets will make nightmares for you. It is very much worth your time, effort, and money to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions. That way you have to do the job only once.