To the best of my knowledge, a Nardi Steering wheel was not a factory option then or ever.
i would guess he cost of a new Shadow back in 73 would have been circa, $15,000.
As for options, I'll scout around for an options list, though it was usually taylored to a customers specific request rather than standard options. As they used to say, there is no such thing as a standard Rolls Royce.