Rare Belgian 5mm Pinfire Folding Knife Pistol 1850's

Really a cool item. Retains a pleasing patina overall with some areas of light pitting. 3 ½ inch folding knife blade has nicks out of the edge. Marked on the blade BREVETE S.G.D.G. on the left side, has S.B. in an oval on the blade. SB marked on the cylinder. Grips appear to be horn, and are solid. There was most likely a German Silver plaque on the left side of the stock, which is missing.
One of the grip screws is a modern replacement, missing the bottom one although they were most likely pins. 2 3/8 inch octagon barrel. This gun appears to have been double action.
Roughly 9 inches long with the blade extended, 5 ½ inches with the blade folded. This is a really awesome little gun.