Knife is 1951 to 1966. The lower case Kabar italicized mark started in 1951 when Union Cut Co changed it's name to KA-BAR Inc. and it was bought by Cole National in 1966. Cole National still used the Kabar lower case mark but began stamping the model number on the blade. If it were a WW2 era knife it would have KA-BAR all caps over Olean, NY (circa 1943-1946), or if an early war knife it would be KA-BAR plain or with a secondary blade marked UCCo or Union Cut Co. The KA-BAR caps over USA was used circa 1947 to 1950.