Mystery number

[alikat]

I have a Norskie airforce M40 helmet offered to me, but am perplexed by this number stamped into the neckguard. Any opinions please? As the liner is not red I am guessing at a modern repro lid sexed up.

[Adravor]

The pictures are awfull, the shellshape looks good to me, the rest not.
But ig. you have to wait for the more experienced to tell you what it is exactly.

[sysyphus]

Indeed pics are bad and too small for a serious evaluation.
However the lot nr resembles the font used for ET or SE. the rim looks correct so i am leaning toward being an original shell

[PotatoDigger]

Looks like a fine helmet to me, the number in the rear of the helmet is referred to as a lot number and is to be expected on every military produced German helmet.
These were added to every helmet of one batch before heat treating.
Probably manufactured by ET or SE since we see the stripe going along the rolled rim.
A stamp with maker mark and shell size should be located on the right side of the inside skirt.
The liner might have escaped being dyed red and thus never got dyed but it and the chinstrap look good from the pictures provided, the price seems very good, too.
At this asking price I would say go for it but it would probably be wise to ask for crisper pictures, but as of now nothing is putting me off.
Luis