Ted,
You are correct on the material replacement issue, however, some people still throw out the % argument.
The seating configuration is original but what the construction was is unknown. It probably had cushions but the slat seating is far more resistant to the mouse and vole population. The seating in the prerestoration photos was made by a blacksmith at the museum and resembled generic walkover seating.
I am no longer employed by the museum but I am told that car is currently stored inside the restoration shop.
I think that I speak for all involved with the project that we appreciate your complements and wish you the best in your projects.
Paul Dalleska