JJ may be working of a physical version, but its not the real version used on screen. His helmet somewhat resembles one of the liscenese lucas products or fan sculpts. So it may be based off physical armor, but from what i see… the helmet is most definatly not based off of teh accurate helmet used in the movies. The armor however is quite nice. I was admiring it in 3dsmax when i dl’d his regular trooper.
Here’s a new pic. I’ve re modelled the knee guard on the right leg, adjusted the legs in general, also remodelled the right knee guard as well. Adjusted the upper arm peice, fixed up some of the wrinkles in the shoes you folks pointed out on scifi3d. (i’ll be fixing the belt, and working on finishing the rear armor next.
This picture features my 3d trooper, composited into pics of replica trooper armor cast from the on screen used armor. (although there is some customization and mixed peices of armor there, its genearlly the same. The Helmet is dead on though. Thats a GF helmet cast from a real trooper helmet used in ANH (which is no longer available since Lucas put the boot down:)) Take a look and read onward.
Test_Composite01
Btw the helmet is the only thing mapped in the picture. The dust on the armor is just painted quickly in photoshop to take away that boring unmapped rendered look 
And now…
Time for trooper school 
Here’s the facts. Very abreviated and generalized.
There are various types of fan made armor, but i’m only concerned with screen accurate armor and not fan sculpts and liscensed artist sculpts which dont resemble at all the thing i saw on screen at a very young age.
There are only 3 storm trooper versions you see on screen in the movies. Each one appearing in each film (ANH, ESB, ROTJ). Technically there’s 4, but the 4th variation was the same shape, but made nicer for close ups. I’ll explain more below 
ANH:
There are two versions in this film. They are from the same mold and sculpt. So they have the SAME exact shape. The only difference is flat lenses/bubble lenses and the number of holes on the frown of the helmet.
The two versions are HERO, and STUNT. The Hero helmets, worn by Mark Hamil, and Harrison Ford for closeups, featured bubble lenses and had 6 holes cut in the frown area.
The Stunt helmet… Which is what you see 98% of the time in ANH… has flat lenses, and 8 holes on the frown. Some versions of these helmets, have high brows to add some variation and character.
There is of course the sandtrooper, which is the stunt trooper helmet, plus backpack, pauldron, and sometimes missing a box on the stomach plate. (probably fell off in filming)
ESB:
ESB had same situation as ANH. Stunt helmets, were all reused from ANH. Only difference is they got repainted. The frown was painted all black, where as in ANH they were painted Grey. I beleive the tube decales were of a different color as well.
ROTJ:
ROTJ is where the shape of the helmet was altered. It was sanded down due to it being hard for the the actors to perform in the helmets, due to their bobble head nature and how they would get stuck on the armor as the actor turned his head.
All ROTJ helmets had bubble lenses. There were no flat lenses. The colors helmet decales were different from ESB and ANH.
SW: SE:
The suits were a hack job mix of ROTJ suits and new parts.
With the exception of the ROTJ version of the helmet, ANH and ESB had the same exact shaped helmet. ROTJ’s helmet was based off the same mold as the ANH helmet, but was sanded down a bit like i said, so it appears narrow and odd.
So there are only 2 shapes to the helmets. ANH/ESB and ROTJ.
I’ve gone with the ANH version because i think it means more to me. I think the ROTJ helmet is odd looking.
Here’s a new comparsion pic of a fan based suit cast from ANH screen used armor and my 3D ANH trooper, entirely hand modelled.
Test_Composite01
As you can see, its closer. I’ve even attempted to model in the infamous “eye bump” located on the left eye.
The only problem that may stick out right now when looking at these pics are… The hand armor, and the stomach armor. They VARIED from scene to scene and film to film in star wars. In this shot you can see Jedi and special eddition hand armor. I modelled the ANH hand armor. The box on my chest armor with the 5 black dots… is upside down. It is detachable on the real armor, and was sometimes rotated one way, or the other, and sometimes not even on the armor (some sandtroopers).
I also own two (replica) ANH helmet which were cast from an actual helmet used on screen in ANH (obviously not liscensed by Lucas:) They are the essentially the real thing you see on screen in Star Wars ANH. The shape i’m modelling is based on it. Thus being more accurate. I dont like the don post liscense helmets, or other black market helmets which were artist interperations of the movie helmets. They dont come close to the real shape and form.
As i said earlier… I dont want to take away from JJ’s excellent work and talent. And i dont mean to sound arrogant. I for a long time have been planning on buying trooper armor, and having read up on many of variations and having been instructed on the variations from people who know FAR MORE than I
That i can guarrantee… I’ve learned quite a bit about the trooper on my journey.
And from what i see… JJ’s is not based on the real helmet. But its still a fantastic image. The armor is very well modelled, but the helmet just isnt true to the real prop. This isnt about ego or being better than JJ. Its simply about right and wrong. If the goal is to make something as close to possible as the real thing seen in the movies, then the referenced design is wrong. The artwork is fantastic though. He may be planning to make a fan film, and the only armor he currently has is that helmet version. And is simply making a digital double. If so, his goal is different than mine. I think his model and image very well done. Perhaps our goals are different. Like you said, hes modelling off a physical object, as are I. They’re just different objects hehe… but my point is one, or atleast the helmet is more true to on the screen image in the films. Thats my goal.
Forgive me Zoo if you know all of this. But i figured i’d make my case anyways.
Also i should add that i modelled the helmet in peices, exactly like the original vaccum formed helmet. So you can rotate the cap, and create a high brow helmet very easily, just like the real thing. Thats what you saw in some of the other pictures. This model isnt high brow or low, its capable of being either at anytime.