South Carolina $5 Note

Since you say you know nothing about banknotes, I'll take it back a step further. In 1861, Congress authorized the Treasury to issue various paper currencies. Prior to that, there was no federal authority to issue banknotes, and paper currencies were issued by individual banks and sometimes States and Territories...sort of the wild west of currency. The currency issued by a bank or State might be worth face value locally if folks trusted the issuer and were regularly able to exchange for real gold/silver. However, that note may or may not be accepted elsewhere. Many of these banks folded and the currency became worthless. Obviously, most of the Civil War era southern issuances became worthless after the war.
If you want to see the breadth of these currency issues, check out https://www.obsoletecurrency360.com/, although I'd disregard the values listed. There are a ton of bank/State issues, which is why most collectors focus on a particular bank, or State, or theme.

Here is a good article on the Dabney-Morgan stamp on the reverse as well.
https://currency.ha.com/heritage-au...na.s?id=3249
There is also an article on where these notes are coming from in the New York Times but it is behind a pay-wall so I can't link it. Suffice to say, a guy at the SC state archives is slowly selling a group of notes that weren't destroyed in 1880 like they were supposed to be. The sales are generating funds for the storage and collection of their state currency archive.

Being a resident, I had to take a look. The reserve prices keep me from jumping in, although it would be fun to own some of these pieces of history.

Regardless, it was worth the time to take a look, even though the duplicated PDFs made it a little awkward to browse (the beige backgrounds are duplicated, the white ones are unique).