My interior was done by the crew who do Air Force One, next door, at Andrews AFB.
First I bought new plastic bits, which are thicker than the original.
They mostly fit, but a heat gun got them spot on.
https://vantageassoc.com/airplane/cessnatwin/337.html
Then the AF-1 crew overlaid plastic with synthetic leather from douglas aircraft interior,
https://douglassinteriorproducts.com...gory/aviation/
I used douglas again to supply local auto interior shop with materials.