Re. the Mk2 Service there are two ways to see this cobblers: first is that some yoof in the advertising dept. perpetuated the military connection idea because it was a good yarn, and nobody conradicted him, so it went through to publication.
Or it was a cynical reworking of history by someone who knew perfectly well that the myth was already entrenched out there, so it made good copy whatever the truth....
It "became known" as the service rifle because that's what was stamped on the cylinder.