This WW2 US M1 helmet is a fixed bale, front seam helmet, as was issued to both US Army and USMC troops throughout most of the war. It has a nice original, WWII USMC camouflage helmet cover on it. These camo covers were reversible, they had a side that was more green and a side that was more brown. They are made out of the same camouflage pattern and same US army style hbt material, as the WWII P42 and P44 USMC camouflage uniforms.
Even after the Marines generally abandoned wearing camouflage uniforms in favor of the plain green hbt P41 uniforms later in World War Two, they continued to wear these camouflage helmet covers. It became, in my opinion, one of the iconic symbols of the WW2 Marine.