I watched that video a while back, and did not believe what I saw, and that was the cap with ears.
I have restored a bunch of the round caps over the years and looked at quit a few original cars with there born with assy line gas caps including 1970 Chevelle's that used the same "Round" Stant vented anti-surge cap.
I would have argued long and hard that the ear cap had not even been made in 1969.
Any thoughts on the one in the video ? Maybe a early engineering test thing ?
Shauger have you seen the video with the ear cap ? Interesting, never say never ?