Welcome tjames, I'm a jamest.
Chuck Maddox, a recognized authority, has some different ranges for serial numbers. Is there a significance to the date or are you trying to authenticate a late bumper?
I was hung up on dates (birth year and all that) but it passes.
Unless you have a dealer receipt with photos next to the delivering womb it's damn near impossible to ascertain.
I am so happy to enjoy the wonderful era's and the ebb and flow of fashion from the turn of the (20th) century to Art Nouveau followed by Art Deco, Modernism, the war, the 50'ies and on and on.
Your watch is wonderful from a wonderful era, might even be my birthyear!
Needs a strap though.....