Was this filmed quite a while ago? I spoke to Stephen Lane via email early 2013 to ask about this helmet and he said he had sold it when he bought another hero TIE helmet.
I only wanted to see a photo of the back of the helmet to see if it had the same box as the other helmets on it as I was going to try to make a nice replica of it.
The Prop Store then started exhibiting this hero TIE helmet.
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That's the one I saw Jez review a couple years back. Might be Stephen sold that one in favor of the one seen on AR. I don't know the exact lineage of the various helmets, but at least one (all black, no grey trimming, silver/grey cogs, sold by Christies in '02) was made at some point with the compad slotted into the back of the mohawk instead of having the pill box mounted on it. I'm going that route with my build, because I think it looks better.
For the pill box, maybe send a message to our much-overworked MonCal. He's done what looks to me to be the best recreation of the pill box I've seen out there. He doesn't part his helmets out, but he may be able to give you some pointers...
--Jonah