Hey Oct,
If you look at the top and second photo, you can see the back side of the chin strap, it looks as though the back of the strap is dyed the same colour as the front, this is a bad sign, as the originals should be only dyed on the front. As with all rules, this can be broken, if some one has messed with an original strap, or you encounter a reproduction that has been made correctly, but to me, this one does not look good.
Best
Gus