Hey guys. Recently purchased this M1, however I am unsure of its era. I know that the webbing on the liner is from 1968, but that is all I could definitively identify. Any thoughts? It is rear seam. The only marking I could find was a "4" on the inside of the helmet. Additionally, the chinstrap might be a replacement or look a little off (as it has rivet snaps). As I am a new collector, I jumped at the opportunity for this helmet as it was priced fairly. However, I am unsure of the authenticity of the shell, though I am confident that the liner (or at least the webbing…) is legit. Please feel free to leave any comments or share and thoughts. See the attached photos. If more pictures are wanted, I can take them and attach them.

Click to enlarge the picture