This helmet consists of an early M1 Steel helmet with fixed bales, early Hawley M1 fiber liner, and what is commonly called a type I USMC camo helmet cover.
The cover has had two slits cut for better fit and this feature is found on most issued covers:
One of several features to look for on an original cover is chain stitching on the beach side:
Further disassembly of the helmet at this time would likely risk damaging the very fragile original liner:
Camouflage helmet covers began being used with the U.S. Marines in combat following the battle of Guadalcanal. Here's this combination in use during 1943: