The -10- mark is reference to the teeth per inch, tpi. That was a great company that made fine tools, you have a good saw. Looking at the medallions, chrome or nickel plate, and the wood in the handle, if it were a Disston, would say definitely before WWII. Am guessing it was pre-1955, due to the varnish on the handle/tote. I have one OVB, vs. dozens of Disstons, yours isn't terribly rare, but I'd have grabbed it for sure.