Re-upholstered?

When I started to dismantle the project, the Recaro seats were thrown out in an early stage as the were very smelly... The interior work was quickly outsorced to my wife, so she started to clean and freshen up the vinyl parts such as the "rear" seats, quarter panels, parcel shelf etc. All these bits and pieces now look as the will be usable and are safely stored in the attic!
She was a bit curious about the Recaro seats as they are upholstered in a black-and-white check, (left on the pic) but through some holes we could see another fabric. When the first seat was dismantled we discovered that beneath the first layer there was another black-and-white check "dogtooth" which was in a fair condition (except from the smell...)
So, it seems that the seats have been re-uphostered in an early stage and the original fabric was kept. We wonder why it was kept, and when it was re-upholstered? As the first layer isn't damaged or worn we wonder if Michael Piech just did not like the original fabric?