Neither the WW2 1219C2/USN MK2 nor the VN versions nor the post-VN nor the currently made versions (Ontario for the government or Kabar in general) were ever "rat tail tang" knives.
A rat tail tang is round and sometimes tapers down at the pommel. The pommels are held on by either threading the tip of the tang and screwing a nut on to hold the pommel OR the tip of the tang is peened down to hold the pommel tight.
All of the "Kabar" knives had what some people call "stick tang" and what others call a full tang - the tangs are narrower than the blade, usually the same thickness as the blade and the pummels are held on by peening, pinning or the tang tip is threaded and the pommel tapped for screwing on and then being held in place by a split nut (first Camillus version) or peening (second Camillus version/all other companies during WW2) prior to the change to being pinned.
Some purists get bent out shape over calling the Kabar tang a "full" tang because the tang is hidden inside the handle. Well, the Kabar style tang is a full LENGTH tang as opposed to a half tang or a 3/4 tang. It is NOT a full WIDTH tang, but neither is it a rat tail tang that they then try to claim the Kabar has. To visualize what a real rat tail tang looks like, look at a rat tail.