Derby S.P. Co. Wm. Mount Sugar and Creamer

This is a matching set of silverplate creamer and sugar dish made by Derby S.P.Co also International Silver Co. It is marked with the numbers 1140 some initial that look like EDNS and Wm. Mount. The look in pretty good shape, no dents, but need polished. I don't know if any of the plating is missing, but if it is I don't see it. They measure 2.25 inches hight and 3 inches across. These are probably from before 1950 but I am not sure, this is a very old silver company and the latest I found their work was the 50s.