Seats badly worn as far north as Canada is indicative of lots of miles. Sun and heat take far more toll of the interiors in the middle and southern states than up here in Canada.

The seat material is quite durable. There usually will be no cracked drivers bolster on the drivers seat for example at 200k miles.

Odometer accuracy indicated is a problem with these cars. Try to take someone along that has owned 123 diesel Mercedes. This actually may be quite important.

Almost never believe the odometer reading unless positive evidence is there or condition suggests it might be so. Most are still pretty good cars at 210K miles.