I made up a notebook with pictures of the factory. Lots of wooden chassis in a row. Someone putting on the aluminum, etc. etc.
I carry it with me and when they don't believe it's wood underneath I let them leaf through the notebook.
I've got one made up for the + 8 and the 3 Wheeler.
It's a lot easier than trying to explain the cars every time.
I ran into a guy with a Model T at a filling station. He had a good quote about these type of cars. He said " Every stop is a car show and every drive is a parade"