Makes sense. What about this blue steel mark? I've seen it on a few other brands of razors but never heard what its actually referring to.
And here, i've actually found that you're probably right. Big cities, such as new york, used 5 digit phone numbers in the early 20th century, which were broken down by dashes like that sometimes. I would have guessed that they were dates.
http://www.artlebedev.com/mandership/91/