RIck,
I believe your "documentation" lies in the condition the car is in now. If someone restamped a VIN, the car would not look like it does now. It would at least be partially restored (or "fixed up"). Originality is the best documentation you can have. I'd rather spend money on a restored car with no docs but plenty of "as found" photos than one with docs and no photos of it before restoration. One could create fake docs, but no one could create that car out of thin air in the condition it's in presently. Some parts may have been swapped 20 years ago, but it wasn't done for deception. The history of the car speaks for itself.
Just my view...
Verne