The bottom line on these cars is the mileage is irrelevant. Some have a few hundred miles when they come up for sale. Some a few thousand. Either way, what you want to know is how the owner(s) treated the car. Was it built properly to begin with? Was it sorted out methodically? Was it garaged? Was the engine filled with the right kind of oil? Did the (Type 1) valves get adjusted properly? When things broke or leaked or sagged (as they inevitably do), were they fixed the right way? Whether the ODO shows 40 or 40,000 miles, these are the questions you want answered.