Remington Cartridge Box / shell Dating ??

Does anyone know of a simple way to date a remington cartridge box or shell. I have a .308 Win box - no zip code for ilion NY - Marked Core-Lokt - Index 8308 - FPO4ND - and 16R. Green box with red and white trim? Styrofoam insert.
?? I think it's from late 60s or early 70s.