1/2/79 Is the second of January '79 if'n you're an American.
That's when it was shipped across the USA, from Beeman's to Northwest Guns & Ammo.
Which doesn't leave much time for it to have been made in Germany in '79, and received at Beeman's in California, on or before "January 2nd".
UK: dd/mm/yyyy.
USA: mm/dd/yyyy.