30-31 Roadster "Hip Panel" Upholstery?

[mit31]

Having a hard time understanding how the 30-31 roadster Hip panels (the triangular area behind the door, next to the front seat back cushion) are upholstered. The Cowl and door panels are easy as they are cardboard panels popped in or screwed flat to the body. The hip panels are somehow material wrapped around the 3 pieces of wood... but those pieces are blind bolted to the body, so I don't see how it can be done.


Anyone done one of these recently?