Boucher (which means butcher in English) is a pretty common name in France. There was a Boucher gunmaker, so I think the name on your gun is probably legit--although under the forend on the barrels would make it a possibility that Boucher was only the barrelmaker. (Quite a few French guns have no maker's name at all. Some have the name of the shop that sold the gun. And some have a barrelmaker's name or initials, where you found yours.)
Because Boucher is such a common name, not likely that the gunmaker and the wine-maker would be the same family. And you do have the French pronunciation correct.
In both cases, if you can post pictures of the guns, we might be able to give you more information. The barrel flats (underside of the barrels, under the chambers) are important because of the proofmarks.
