Vietnam Era M1 Helmet with WW2 Reconditioned Shell?

[old tanker]

We used the US M1 helmets when I enlisted in the CDN army in 1974, and even then I could tell that this one was different from that one. We had early and late, new and first issue types...and issued them without and care whatsoever as the anything. If it's a serviceable helmet, it's out there. We used them until we destroyed them, and destroy them we did.

It's you collectors that think they're something special...

You got it. It was the same way for me when I enlisted in the US Army in 1968. There were a few WW2 helmet liners about, the chin straps changed styles, but we pretty much used front seam, rear seam. fixed bail, swivel bail and every kind of paint the supply room passed out without regard to period correctness. The Kevlar helmets starting replacing the steel pots in USAREUR during the mid-Eighties.

As for the markings, very possibly identify "Delta Company, 3rd Battalion, 2nd Training Brigade" at any of the US Army Training Centers before the Army began renaming training units with historical regimental designations.