In this episode, they show a $50 large size bill from the 1870's. I collect old paper money myself, and I have a reference book that shows this note. It appears they used a real one for the show. Well, get this: in today's market, that actual bill they showed is worth at least $10,000, and depending on condition, as much as $87,000!
I wonder if the studio prop department at the time (1961) had some old paper money that they kept on hand for just such occasional uses. Or, if they borrowed this note from a collector or a high-end coin shop for a small fee.
In the episode, the premise was that $153,000 in such old money was found. We're talking in the tens of millions of dollars in value today for an amount of old notes like that. Whew! Oh--old US national currency issued by the United States was always redeemable at face value. It was the Continental Congress money that wasn't. Of course, you'd be crazy to redeem a $50 bill for $50, when it could sell for as much as $87,000!