Stockman date of manufacture?

[Bowzer]

I picked up an older carbon steel Camillus stockman on a recent trip. It has black jigged delrin scales, a shield-shaped shield that appears to be nickel silver, nickel silver bolsters, and brass liners. It has the standard stockman blade configuration. The front of the clip blade tang is stamped Camillus New York with a line between the two words. The reverse side of the same tang is stamped with the number 67 which I take to be the model number. The other blades are not stamped. My question is: How old is this knife and is there a way to tell the date of manufacture for older Camillus knives? The blades on this knife look a lot like the same design of blades on an older Camillus whittler that my mother says she bought in 1967, so I am guessing is is around the same age. Thank you.