It may not be a Sandman but most likely is. Do you have the VIN tag number, should be 8M70TDL2729xxQ or 8M70TDL2730xxQ.

Look for:

Evidence of wires for ammeter in dash being part of the original wiring harness.
Factory console mount at rear of cabin between seats, and 2 x screw holes in front of shifter hole. Has to have these to be a Sandman.
220kM/h speedo.