This is most definitely a dutch helmet. A family members bother in law is dutch and who has done national service confirms this. He has one identical in his collection, with the same stamp markings.
Judging by the tack-welded bails, suspension, chinstrap and color, you have a post war Dutch Army helmet, probably made in the late 40s-to early 50’s.
Hi, I’m new here and just stumbled over this thread. Yes, it’s Dutch post-war. This type of helmets were used bij the civil defence or “BB” The chinstrap/buckle is the same as the postwar, pre-kevlar M1 clones. I had one in my armydays 1984/1985.
Gr
John
Dordrecht, The Netherlands