Guess respect on both sides where due either way the wearer of the said helmet quite possibly met a sniper or a very good open sight shooter.
A few years ago, we tried engaging head targets at 600m with open sights with MkIII's, No.4's and Mausers due to the colour of the core flute black target on yellow background plus they were in grey sand you could barely see them with the naked eye let alone sight them but we had some fun.
Sadly all the fun has gone from Milsurps shooting in our state as we are no longer allowed as civilians to shoot at Fig.11 or 12 targets also our walk up multi positional shoots AFAIK have been canned as well which was 3-2-100m.
Bulls eyes only now how exciting is that!