Does anyone know anything about the ink stamp? And am I correct to identify it as a Nam' era lid?
I've also found very faint traces of red paint on the chinstrap, and on the exterior of the helmet. I agree that it might have been used by some deck hand or gunner. Now I need a nice period liner to go with it. After a preliminary clean, the chinstrap is indeed brown, just very dark/dirty.
EDIT - A quick clean, and here's some close ups of the chinstrap:
As you can see, it's in bad shape, and I'm scared to put any stress on it so it doesn't rip.