Looks like one of the many variations on a Martini to me. Am I missing something? Sidelever instead of an underlever; not too odd. Kinda slow, but gets the job done. Rifle seems well made and finished.
Thanks for the compliment Mike.

The lever on the side dates back about 20 years before the Peabody was patented, and the function is somewhat different. The lever is connected to a cam that moves in an oblong hole in the floating (no screw in the back to hold in place) breech block. The breech block actually moves forward into the chamber and seals the breech when closed, necessary when the guns were still case-less percussion breech loaders.
John