The KA-BAR brand originated as a trademark of the Tidioute Cutlery Company. Tidioute was later taken over & renamed the Union Cutlery Company which continued making the brand until Union eventually adopted it as the company name in 1952. Cutco Corporation later acquired the company in 1996.
KA-BARS can be very hard to date in my experience. That said any Dog's Head knife with this cam type lock that I have seen looked to be a pre-WWII knife to me. Maybe as early as 1920's. Is the tang stamped Union Cut on the pile side?
If I have seen further it is by standing on the shoulders of giants.