And they just never come up for sale anywhere. Well, a fellow T206 back stamp collector located these for me recently and I was able to pick them up. He picked up one of them for me when he saw it and then I was able to get the other one.
Here is Ball with the number 81 on the back. This is a very nice clear stamp as well.
And Sweeney with a 142 on the back. This is the highest number I've ever seen on one of these purple number stamps.
These back stamps always have a lot of pencil writing all over the backs as well. I have no idea what any of these numbers, pencil notes, etc. mean but I just love the numbers. Like I said, they never show up for sale so I'm just thrilled to have them.
Enjoy the hobby all...however you like it.