Mcdonald Territory Dispatch Stamps

This is about as far back in the book as I can think of, to the point that I am wondering if it is real or a cinderella. Some things I am reading suggest they are legitimate, but others not.

Here is a short read about the McDonald County secession of 1961.
https://ozarksalive.com/that-time-m...om-missouri/

And a short read about the private dispatch stamps that were prepared to deliver mail to the post office.

https://www.qsl.net/kg0yh/mcdonald.htm

I found this cover at a local antique store, here in SW Missouri, which got me searching for information.



Thoughts?

Anyone have any further information about the stamps or their usage?

A very interesting story.
When I first say the cover shown, my first thought (before I saw the date) it was from the 18XX's something.