The shine, the sharp angles... does not look right to me (compare with the other one). But I may be wrong. And this would not be a reason not to purchase the helmet anyway.
I know about the possibility of small cockades being worn on M15 cavalry helmets, even though I saw no proof for it. But I would always go for the best looking version. It is like having a hessian M15 with a round spike base... yes, these did exist but for me the real appeal of the hessian helmet is the cruciform base, therefore I would not go for anything else. Just my opinion though...
Cheers,