The helmet, and the rest of the armour, is cast from an original set, up close the helmet looks a little rough to be honest but that's how it's meant to be, they didn't want to change anything it's exactly as it was including all the lumps and bumps. There are many different makers of stormtrooper armour but this is the only one that's actually cast from an original set, there is another maker (Andrew Ainsworth) who claims to make them from the original moulds but it's all lies, he did cast the originals back in the 70's but he didn't make the original moulds and he doesn't have them either.
The full set as a tailor made commission, including the E11 blaster (also a screen accurate replica made from a cast of a sterling machine gun etc), boots, under suit, and neck seal is £1450, this one was a little more as it came with a limited edition helmet with a stand and plaque signed by Brian Muir one of the original cast. I got lucky though and got the whole lot on eBay for £700. It sounds like a lot of money but there's an awful lot of work that goes into making it and putting it all together.
If anyone's interested this is the RS website page for the commission
http://www.rspropmasters.com/product/co ... mission-2/You can also buy it cheaper in kit form and put it together yourself.