If you want to know more check out the RPF research and build log for the Rogue One Rebel Helmet build. Its a great group build that I'm proud to be part of.
If your looking for the Correct version here are the things to look for;
Curve of the Helmet, the Grey one on the left is the 1970's M1, right is the WW2 version.
|rpf member BobZurukle|
The seam around the bottom of the helmet is joined at the back, If you find one with the seam at the front its a WW2 version.
Your straps may vary and could have been repaired with a plastic rim for the strapping to fit to the inner helmet, its your choice to decide how authentic you want your build to be. here is an original inner with original strapping.
|screen capture Rogue One trailer.|