I think you need far more better pictures to let the experts judge!
Judging by the photo, the decal is clearly in the wrong place/position, and it looks ike there is another decal underneath it.
I know very little about ss helmets but just looking at these pictures the decal doesn't look right!
The decals should be directly under the vent, lined up square, with a 3mm gap between the vent and decal. Have a look at others posted on this site to compare.
Regarding the helmet that started the thread, it is a Pocher wannabe runic decal on an M42 shell, big red flag.Pictures of that quality - another red flag. Don't waste anymore time on it. Jim G.
Looks like someone took a decent M42 and slapped a fake SS decal in it to spice it up. Assuming the rest of the helmet is correct, that decal could be removed and you'd have a nice M42.