No real good idea what he's talking about, reeks of BS to me.
Here's one thing I do know though:
For quite some time (close to 10 years) the original style cluster hasn't been available for 129 and 140 chassis.
If this car has the old fashioned "reel" odometer (kind of like a LasVegas slot machine aka "one armed bandit", then I'd say the speedometer and mileage are original, or replaced very early in the life of the car. The speedo that is available now has the digital odometer, say like a calculator display.