You're right on the '67 release date Pete, and the fact that original UK issue was on the Stateside 20xx series plus the U4km on US copies confirms that, but not all reissues/boots conform...where the original masters were used, or wher the bootleggers could confuse the issue even more, the original delta number was sometimes used. Buster and Eddie comes to mind...
One thing though, why do the Hoagy Lands boots (or are they second presses?) have W4KM, which would date them to '68 (don't think V was actually used). That would date them to two or three years before it became popular, surely no-one was thinking that far ahead?
Hippo.