The earliest pinfire shotshells from the 1830s have only ever been seen in 24g even.

Also, if you go back that far though 24g (in Paris) did not mean the same thing as a later English 24g.

However, I was looking on the IAA forum to try to find a couple examples for your specific question. This would be a good one.

This is a German 24g by Utendoerffer who ceased operations in 1889 when they sold to RWS. So definitely made before 1891.

[Linked Image from photos.smugmug.com]

https://AaronNewcomer.com & The Lefaucheux Museum