Good luck to the owner if they achieve the asking price. Comparing this van to the value of other vehicles is pointless, as you would be looking for one particular vehicle, which is a van.
As for originality, there would probably be half a dozen 100% original sandman's in existence. They have all been changed throughout the year's, cam's, carbies, brake's, it's all been done long ago, and some recently. Today people class modification as making the vehicle more reliable.
When I had mine it was about making them go....Then making them stop also.