Unless the car has something interesting about it, that can be validated, then I don't believe there would be additional monetary value placed on early normal production cars.
With the 65-66 cars, there's a lot of unknowns without the records, so anybody claiming 'first of' or 'one of x' has no concrete evidence to support it. If one could say they had the first K code built of the 3 body styles, that might add some value, but no way to validate.