Original U.S. WWII 1942 McCord Fixed Bale M1 Helmet with Vietnam USMC Camo Cover & Westinghouse Liner Night Sights so this is definitely a

so this is definitely a service used example

which look to have read 39

however examples such as this were bespoke

In the end

somewhat worn with 250 years of polishing that appears to read:

Original U.S. WWII 1942 McCord Fixed Bale M1 Helmet with Vietnam USMC Camo Cover & Westinghouse Liner Night Sights so this is definitely aOriginal Item: Only One Available. This is a very nice example of a genuine WWII Front Seam Fixed Bale M1 Helmet made by McCord Radiator, fitted with a very nice liner by Firestone. As with many WWII helmets, it was kept in service long after WWII was over, and looks to have been reissued for use in Vietnam. The outer shell was repainted, a new sweatband was fitted, and it was issued with a USMC reversible camouflage cover. This has the correct U. S.