US GI M1 Combat helmet Liner shell used Good condition Korea Vietnam

This is an original 1947? dated M1 combat helmet liner shell. This is used. I have found a small split in the front edge and a punch spot in the dome. (see pictures) Looks like it still has the first coat of darker OD paint on the outer.  The inside is decent. The suspension is showing it's age and there is some rust on some of the attaching hardware. This has M11 and 47US on the inside of the dome. Possibly a run number and a date? I don't know, I'm not a US helmet collector.