Need help with Cap helmet lining

[TKSteve]

So I've gotten this far with this Cap helmet for a friend, but for some reason, the leather parts are breaking my brain. I can't find a usable pattern anywhere, or even what it looks like under the strapping. Can anyone lend me a peek?

 

[Godspeed]

This is what I came up with based on a mix of analyzing movie stills and what other makers have come up with, so not 100% movie accurate but I think the spirit of it is there. On the right hand side of the helmet, the piece of leather at the back-- the rectangle with the rounded corners-- and the trapezoid piece have velcro on the back of them so the chinstrap can be undone. On the other side those pieces appear to just be sewn together with the strapping and the leather.