The leather is turned with the hair side out; it's especially apparent on the visor and neck guard. The neck guard is shaped incorrectly, too. This appears to be a modern shell which has been modified with an original front plate and M91 posts. The spine is unvented and does not attach with a square nut. There's no interior reinforcing disc inside the shell and there aren't split brads holding the spike in place. It doesn't appear to be an old helmet with a new liner, but a new helmet with an old plate. The stamp is odd, too. Where's the regimental stamp, the size marking, etc.? The helmet looks a lot like the replicas here:
http://www.zib-militaria.de/Preussische-Pickelhaube-1" onclick="window.open(this.href);return false;
http://www.yatego.com/asmc/p,4ea1779d026e6,4627914cb981d9_3,pickelhaube" onclick="window.open(this.href);return false; :thumbsdown: