Yes, the Riddleberger Act is a real thing.

Here's an excerpt of a Supreme Court document:

"Still another act, approved March 19, 1884, required that all coupons received for taxes beyond what they would have been exchanged for under the Riddleberger act, should be charged to the bond from which they were clipped as a payment on the principal of the bond."

However, please note that the Riddleberger Act of 1822 is named RiddlebErger, not RiddlebUrger. I had nothing to do with it.