Stirring the pot
I agree, and I know I'm going to see these guys on Saturday and I bet they'll have more to say.
You can shift the conversation to the preservation of buildings and art. Vehicles are pretty much in the same boat as buildings and properties in in terms of both professional standards for preservation (called conservation in other English speaking countries) and in practical issues. By practical issues I mean utility - these are not purely pieces of art, ownership - the vast majority are privately owned, and economics - these are one of the more expensive items a person or entity owns.
You can note that the Secretary of Interior Standards provides for
rehabilitation, and
adaptive reuse of properties that for various reasons can not be, or should not be
preserved. Additionally the trend in the past couple decades has been a paradigm (academics love words like that) of preserving rather than attempting to 'restore'. And another (which can be taken to annoying extremes) is that any alterations should be obvious so as not to confuse people as to what is original and what is new.
Since this is a privately owned vehicle, its historic value if any is a typical example not a unique or special property, and still has value as a working, driving, utilitarian piece of machinery clearly there is plenty of room of other options than 'must restore'. In fact even where there are local controls of privately owned property designated historic, with few exceptions they are limited to the exterior that is publicly visible.
Good luck!
