This is the only ad i see in the database ranging from 1953 throught 1960. Looks like the dial in this ad is not two-tone, yet I see a few two-tone examples in the database. I'll get to the library (again) and look through the period rags and see if/what I can see. I've got two I'm gonna add to database: Left is L3 8AC 21j w/ L4 caseback. Right is L7 8AC 21j w/ L8 caseback. Someone got carried away with electroplatting on the charcoal dial example I have....as I can just faintly see the dedication to KEN and the other markings are not as easy to read as my 1954 caseback.