my manual says it is for all VF machines numbered 2,705,000 and upwards. Needlebar calls this "Style 5) and says they started production in 1915. I think they kept making them until they went out of business in 1924. Jim's machine is 3,783,xxx and mine is 3,766,xxx and Needlebar has one 3,374,xxx that they state is a late model.
So I'd say yours is likely 1915-1916, where Jim and I have machines more likely to be from the early 20's - but that is just an educated guess.
The manual has no date, but it does have a price list that says "All prices U.S. Gold" though someone crossed them off in pencil and wrote "all prices void" at the top.