Check some of the other things that are indicators of use. My 76 has about 66K miles on the odometer. I changed out the headlights recently and one was a non-halogen German sealed beam. I bet those were OEM and don't imagine you could get non-halogens in the last 15-20 years, so I thought that might be a pretty good indicator of little use.

Check pedal rubber, etc., altho pedals are easy to change. Is the spare tire OEM? What tires are on it and can you figure out the date codes?

Get a VMI from MB, which would show when it was brought into the dealer for service, and the mileage. Do you have any earlier service records with mileage? Did MB do the subframe recall work, and what was the mileage when they did it?

Good luck!