@WillyZee - thank you, o-rings arrived today.
Before:
After:
It was a snap once I looked at what I was doing. I had a couple-few false starts. The o-ring started going in place, then 'not'!. Then I looked at the brass pin and realized it was pushed down. I raised it gently w/ a small screwdriver, and the next attempt did it. Then I gently pushed all around the o-ring to make sure it was seated. The 'hint' picture Brandy send me was a life saver. Worked like a charm.
The Buna black rings you sent do look a teeny, tiny bit fatter in diameter to my eyes. But they work just fine. (Sorry for the blurry picture, it was a free-hand macro shot w/ unsteady hands).