Good idea Neil and that reminds me of two in the NE corridor:

Hatch & Sons in Massachusetts had two, one a 93 with only 39k on it and the other was a 1993 6.0 with only 24k miles on.
They can be reached at 508-358-3500 or at hatchandsons.com.
They also should give you a comparative idea since they deal in many MBs and specials Another thing they do is restorations so they could also give you an estimate.

Tobias MB
4 MBs