VTG US Army Military M-1 Helmet with Liner Rear Seam WWII Vietnam or Later ? 38B

Unsure when this was used. Vietnam era? Older/newer? Has wear. Please ask questions as I know nothing/very little about this. I think this is a M1 but not positive. Questions or concerns? Feel free to contact us, Ryans Rust. We use recycled packaging when possible. Pre-owned items may contain signs of wear or flaws not pictured. We try to describe our merchandise as honestly and completely as we can. Thank you. The number/letter that may be at the end of the title is our inventory number. INVENTORY-34B