IDK if this is real or a repro. Examine the ink on the signatures. If it is the same as the rest of the bill, it is a reproduction. If they are different colors, it could be good. I am not saying these are faked, but they made TONS of reproductions and some were artificially aged. A real one signed by Sam Houston is probably very valuable.
I agree. It does look like the ink used for the signatures did bleed through to the backs, which is a good sign.
Thats interesting. It is different. Different shades of brown on everything that was hand written in. They dipped feathers in ink back then, didnt they?
You might want to make contact with Denly's of Boston or Executive Currency and send them some photos with an email. If real they might be able to give you a ball park valuation. If real this might be a candidate for restoration by the right people.
It had been given to my dad from his uncle who was a coin and stamp dealer all or most of his life, who died in about 1987. Most likely it is real. He had no children, so he gave coins and bills to my dad.
This is a specialty item. So there may not be a set price. A Sam Houston collector would want it, as would a currency collector, it would have to be appraised. And condition is important, if it can be restored that might be a way to go but that will eat all the profits. As a family heirloom, if you aren't going to sell it, then restoration is the way to go. Because it will just disintegrate further. It will need some kind of currency protector also.
I know zip about paper currency and ephemera like this, but I will say that it looks convincing enough to me for the time period. If it's fake, somebody did their homework. This might cross over into autograph territory if that's a real Sam Houston signature.
You could also try posting it on Collectors Universe, on the Autographs forum. https://forums.collectors.com/categories/autographs-forum
When I mentioned the repros I was thinking of CSA notes, but this is 25 years earlier. Things signed by historical figures can be very important.
As the other Texas, note, this is real, similar value to the other, $150 or so. It is most likely not Sam Houston's signature, I believe his secretary signed most things for him as I believe he had limited use of his signing hand.