I have one of each, both leather handled full-size models. The serrated one gets fondled a lot, and that's about it.
In WWII these were made by Union Cutlery (trade name "KA-BAR"), Camillus, Robeson, and PAL. After the war, existing inventory was used up until 1960, when Utica Cutlery, Conetta, Camillus, M.S.I., and, lastly, Ontario got into the mix. Ontario holds the current contract. Case made the M3 Trench knife during WWII but made no MK2s under government contract. They did submit a prototype MK2.