Kind of a quasi-Miquelet lock, except the mainspring is internal. Now that I think about it, I think DGW called it a Lazareto lock or some such name.
By the way, although those African trade guns really get panned now, just wait for a number of years. The NW gun used to get the same reaction years ago, they were just thought of as pieces of junk. They should, however, be thought of as trade guns, and, as such, pieces of a fascinating history of trading firearms to indigenous peoples. They've got a history behind them, just as the NW gun, the Carolina gun, or any other gun made up specifically for trade with the natives.
The prices will go up on those, but it may take some time. In Buck Connor's book on the NW gun, "Success in the Fur Trade", he notes his father wishing he'd bought more NW guns at the enormous price of $8. Will we think the same way about those African trade guns some day? Probably.
Rod