That Ebay link is to a guy that has 239 NEGATIVES and doesnt even sell in the Mopar circles?!?! In fact the link above is to an Ebay listing that ended.

There are no brand new OEM grommets. There may be a few (damn few) NOS ones but who would want a 50 year old rubber part sealing their gas tank. Like driving on 50 year old tires.

Someone mentioned only one vendor selling the same grommet. Wrong. Everyone and their Asian brother make these now. I have personally tested tank grommets that became soft and swelled within hours when put in a can of gasoline. I could NOT sell this garbage. We have our own made in Akron Ohio, the rubber capital of the world. I spot test every shipment by soaking in gasoline because accidents could happen and the wrong material used.

The other one I see and hear about from customers are the rubber elbows used on fuel filler tubes on 66-67 Plymouths. I'm shocked we haven't heard of lawsuits yet.

Buy where you want but soak in gas before installing.