Your Imperial knife marking almost certainly refers to the Imperial patent (2,391,732), no? It was granted to Michael Mirando on Dec 25, 1945, and assigned to Imperial. If you are suggesting that Camillus is touting one of their rival competitor's patents in their own ads, Jock, I suppose it's possible, but highly unlikely, right?
I am not sure about bone handled 4-blade "camp knife" style pocket utility knives during WWII, but there were only two companies making the stainless steel handled (future "MIL-K") versions during WWII: Kingston (USMC and Army) and Peterson (Army only). Kingston was a joint venture, formed in 1943 by Ulster and Imperial, joining forces to make knives for the war. It was dissolved in 1947. All the Kingston knives had "Kingston" on the bale, along with the "U.S. MARINE CORPS" marking or nothing (Army version) on the scale, and a "PAT. PEND." marking under "CANOPENER", squeezed together just like that, on the can opener blade, and nothing but "USA" (no name, no date) on the tang of the main blade. That PAT PEND notice is referring to the Imperial patent.
My interpretation of the Camillus ad is that it is probably referring to their own in-house can opener design (EDIT: there is no mention of a patent in the ad) and that they are being very liberal (bordering on misleading) with its development "in conjunction with the U.S. Navy" camp knives during WWII. They were involved, but it's my understanding they did not start making them until 1949.
Our host has a 1945 Kingston 4-piece military utility knife and he has studied this a lot closer than me. I would defer to him.