The new style cluster will come with whatever mileage the dealer specifies, they are supposed to give the mileage on the old cluster.(As a matter of fact MB will reject an order for a "0" mile or no mileage stated speedometer.
If you were to locate a used one, a speedometer repair shop "should" be able to change the mileage to what your car is presently at.
On a used digital (LED), no idea how it wold be changed....not saying it can't, but it would be beyond the scope of what could be done at a dealership.

Gilly