In 1954, the 7.62 was still in development. Wasn't "NATO" until 1957. That Lapua stuff is just another commercial .308 load. Lapua stuff is really expensive here. Horrendously over rated as well.
No Scenar bullets until 1988 at all. Not much Lapua ammo loaded for the commercial market until 1984 either.
Finlandicon is not part of NATO. So that ammo is not NATO issue.