This particular helmet appears to be in early-mid 1980s trim. If the shell is American made it will have a heat lot number stamped inside the front of the brim. The number can be used to date the steel pot itself. The liner, chinstrap and cover appear to be 1980s production but the steel helmet itself may be much older. If you are able, take the cover off and look carefully at the seam (rim) of the helmet. If the seam is in the front, it’s a pre 1944 production pot. If the seam is in the back, it’s a post 1944 production pot.