They don't look like authentic decals, but I'm confused about the paintwork here which looks oddly flakey, leading me to be concerned about the authenticity of the paint work in general. I'd be interested to see the whole helmet.
I have had success with removing paint with acetone and cotton buds.
I agree with Douglas, this one could be a movie prop? The decals looks like white base and then black & red are spray painted.
Hmmmm, I'd be inclined to leave it as is. Not saying it is period correct but any removal will further booger up the appearance. I note the air vent is stuffed with something - maybe straw. This was done commonly to prevent the helmet from whistling due to wind - especially by those on guard duty. NH
I'm not familiar with these cut out helmets but I suspect it's entirely repainted, over a rusty shell causing flaking. I will be interested to hear from those who know better than I.
Have a photo of the inside ? Any markings visible?
This helmet came out of a small gunshop in South Carolina. the liner is not metal, it's a heavy leather band. Sure ain't German. Probably/certainly fake. Also, centered above the ear cut-outs are rivets holding a chin strap(!) I'd call that fake. Certainly nonstandard. Shell may be legitimate, however. The cut outs are flared, unlike known fakes I've seen. Stampings inside the shell's rim, if any, are obscured by paint.
My feeling is the whole thing is fake, but like I say I don't know this particular model very well. As you say, the liner and chinstrap is certainly fake, add to that fake decals, dubious paint and a poorly made rolled rim to the interior and I think it's not looking good.
The inner rolled edge looks crudely done ,is the E.T stamp present ?