I.D. info in a helmet

I picked up this Japanese combat helmet recently (that's my son Andy wearing in...I'm a bit older!). I don't know if it's clear but can anyone decipher or at least explain the ink marking inside on the lining 'pillow'?

[blinky]

The left side of the stamp is the date, the first two kanji are "showa" 16 or 1941.

eric

The left side of the stamp is the date, the first two kanji are "showa" 16 or 1941.
eric

Thanks!

[Eric Doody]

The markings to the right of the Showa data are the manufacturer of the liner. (The markings are too faint for me to make out.)