Roughly 1998 I was the middle guy in what I was told was 3/4 of the Sahara Plaques to Jerry Wall.
They came from the controller of the Sahara who was the controller of the Fiesta at the time.
I have posted this several times.

He had them in a storage locker. This find could be the rest of them.
The seller was later murdered while unlocking his front door.

I think rare was never the right word for them.