Article about: In October 1944 the rim material changed from stainless to the same steel that the helmets were made from (Hadfield Maganese). Evidently, for some unknown reason, at the same time, the weld
the quick release chinstrap came out right at the end of the Vietnam war ; actually at a period when the troops were coming home. so its probably a post war late 70's or 80's lid. i had one just like it.
i sold mine a few months back with a what i later figured out was a German m1 liner, a woodland camo cover and elastic band for 50 bucks. mine was in great shape. so just the lid, maybe 30 bucks if your lucky. but i wouldn't go less than 25. post Vietnam war helmets like the 1980's ones are around especially on ebay. i do not pay more than $40 for a complete one. condition is key, the one i sold was in great cond.