I am not sure how I missed this Béringer stuff and your article! (probably the same way you must've missed my Lefaucheux-Béringer article on the topic):

But Lefaucheux was also making "lever-over-guard" designs by at least 1835. I think this was one of the design characteristics he sued Béringer for using a couple years later. Béringer also sued Lefaucheux and in the end they both settled with Lefaucheux licensing some of Béringer's cartridge characteristics.

[Linked Image from photos.smugmug.com]

See section g which translates to: "same key using the trigger guard as a lever."

And a pistol from my collection using the system. Shotguns exist too:

[Linked Image from photos.smugmug.com]

[Linked Image from photos.smugmug.com]

But it is definitely still the typical early double-bite system.

Clock Guns, Pauly Guns, Pinfire Guns and Pinfire Cartridges