Meaning of Markings - Matching Fixed Loop Shell/Liner Set

[Masonk]

Hi All,

Acquired this helmet the other day, and am trying to understand the meaning of the markings. I'm guessing some kind of NCO/Officer or TAC markings? Was hoping someone could help decipher, or have maybe stumbled upon similar markings.

Some basic info on the set. Shell is a fixed loop. Hard to make out the heat stamp. Liner is an Inland, and has seen better days, however is an earlier example with a double wire sweatband. There's a laundry mark, however there are 61 hits when I search the enlistment records, so no way of narrowing down the possibilities.

Helmet and shell appear to have been together for some time based on the overall wear.

Comments good or bad are welcome. Thanks in advance!

First up, photos of the shell.

[Masonk]

Photos of the liner:

[Masonk]

Markings on shell and liner