Need help for identification M1 Helmet

Hi. 20 years ago I was buying a M1 helmet, liner and cover in a surplus store in Switzerland. Now I try to identify the date of manufacture and the manufacturer. It would be nice if you can help me.
Shell is stamped inside 19901
Liner has the Firestone logo and No. 26
All I can read on the cover is

....MET CAM
....DUCK....ERDL....PATTERN
...SA...00.....1701
...415-105......
Thank you for helping me
Some pics
https://www.milsurps.com/images/impo...ac1fbda1-1.jpg
https://www.milsurps.com/images/impo...44f40c58-1.jpg
https://www.milsurps.com/images/impo...f9316c2d-1.jpg

Rough guide to the US M-1, M-2 M-1C shell
Rough guide to the US M-1 liner makers

There's a couple links to get you through this. All the info is there.

Thank's Jim for the useful link.