I have this cup, but I don't know anything about it. Can you help me figure this out? It's 4 inches tall and 4 1/4 at the mouth. The numbers 403 are stamped into the bottom. And I know it was made before the 1940's, I don't know how much before because that when my mother remember seeing it as a kid. Please check out the picture, I appreciate any help I could get.. Thank You.