I'd say a lock from a commercial "military style" musket, probably made in what is now Belgium. At the time it may have been described as "Dutch"... depending on how late it is. We don't have the size but it looks very much like the lock used on a very common pistol that is known to be Belgian made, probably from the 1830s. Those pistols have a flat bottom grip, often with a ring mounted in it and no ramrod. Because they are quite similar to a late British pattern single shot percussion pistol, I've heard it speculated they were made for one of the Indian native states but never delivered. Sears Roebuck and others were selling them at the turn of the century for something like $3.50.
