The metal parts--the Kugel and plate in particular--aren't shaped quite like originals. If the pictures weren't so dark, the stitching on the body would probably be another sign.
The devices used to attach the metal parts to the shell aren't like real ones, either.
The artillery helmet appears to be one of the copies coming out of the U.K....much like this Prussian infantry version:
http://www.ebay.co.uk/itm/LEATHER-GERMAN-PICKELHAUBE-SPIKED-HELMET-/181254773404?pt=UK_Collectables_Militaria_LE&hash=item2a33a05a9c" onclick="window.open(this.href);return false; (The leather hasn't been replaced; it's 100% fake.)
Here's a replica that seems to be made much like the artillery helmet:
http://www.ebay.co.uk/itm/Wurttemberg-Other-Ranks-Pickelhaube-Helmet-/111145543676" onclick="window.open(this.href);return false;
Note the seller identifies it as a replica.
Even the Adrian helmet is being replicated now.
http://www.ebay.co.uk/itm/AH6141-French-Adrian-helmet-WW1-SPECIAL-OFFER/151066565909?_trksid=p2047675.m1986&_trkparms=aid%3D555003%26algo%3DPW.CAT%26ao%3D2%26asc%3D29%26meid%3D2581506517587039849%26pid%3D100013%26prg%3D1013%26rk%3D3%26rkt%3D15%26sd%3D111134393311%26" onclick="window.open(this.href);return false;