Look at this : http://cgi.ebay.com/WW1-Pickelhoube-Hessen-officer-helmet-Vintage-L-K-/260807379775?pt=LH_DefaultDomain_0&hash=item3cb954cb3f
This "thing" looks like an awful repro.
:evil:
It's very damaged, look at the top : it's not horizontal.
The rabatte looks to be torn.
The plate looks rusty, and the chinscale look too short to be originals to the helmet.
A good deal at 500/600$, but at 800$... :o