In my humble, non-expert opinion, I thought it was a real example also, made entirely different than the typical fake ones we normally see on fleabay.
For $821, someone got a huge bargain, I believe.
The last time I saw a near-perfect set of large Jaeger-zu-Pferde or Kurassier kokardes like these sell, they brought roughly $600, more or less.
Even without having the kokardes in hand, I'm convinced they were originals, just on the wrong helmet.
I'd say the liner is the same as PickelMax's. His example has the same cut of black finished leather, with his liner having flaking on the finish probably due to a degree of dry-rot of the leather. The eBay example appears to be the same leather liner, just in nicer preserved condition.
Joe's photo shows the same style mortarboard that is very thick cut, and I believe the photo also shows the felt is 3-layers thick, as was the eBay example.
I do agree with Karel's thoughts that the stitching on the top of the mortarboard looks like someone drunk or hungover did the stitching job! :-"
All the Best,
Alan