The best way from all the seats I've seen to tell if they are original or not is the pulls for the Zippers in the back. Original ones were small and most aftermarket is either big pulls or Velcro.
The frames, hardware, and padding for the bolsters all look right. I never seen the material on an Opel seat before - but hey, doesn't mean it wasn't an option somewhere.
I suspect those are original seats, that have been recovered.
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