Never seen that before, but I have fired a box of 7.62x39 ammo, from 1939, and it was French! I saw the empty cardboard box in the ammo case, and when I read it, I thought it was funny that 60-year old ammo shot so well as it did!

It said something like

"Metalfabrikken

(gibberish) 7.62x39 cartouche

Anul 1939"

It looked like any old cardboard box, I wonder if any of you guys know if it was worth anything?