Yes there is a difference and no there is not a difference.
There is not a difference in that the knives are made to the same specifications and of the same materials. Well, except the newer version had its leather disks treated with an antigfungal agent.
There is a difference in that the guard marked was made in late 1944 to to end of the war in August 1945.
The one that you show in your pics, with US over CAMILLUS NY were made during the Viet Nam war era after 25 March 1962, when Camillus submitted a sample for approval and 01 February 1974, when the NY was dropped from the stamp, although the VN war was already over as far as US involvment is concerned (1973).