[NYNick]

I'm assuming it's an air cooled car. If so I'm not surprised the dealer isn't budging on price. I am always suspicious of cars of this vintage and mileage. It's 30 or 40 years old after all. Asking for justification of the low mileage (to justify the price) is not an unreasonable request if you ask me. Carfaxes usually have data on registrations. Those usually state the mileage at time of registration. If not, the dealer must have SOMETHING.

But, there are visual clues to look for. How's the rubber on the brake pedal and clutch pedal. Worn or new? How's the left bolster of the driver's seat? How's the upholstery?
How's the paint in all the hidden areas? Door jams, under the frunk carpet, wheel wells?
Your visual inspection is everything.

And yes, speedometers come out fairly easily and have a date code on them. That doesn't mean somebody didn't drive around for years with the speedometer disconnected, but it's another clue. Good luck getting them to let you do that, but...

Lastly, always get an independent PPI. Worth every penny for what I'm sure is a many tens of thousands of dollars purchase.