Sounds like it was raped for a 1 tonner in the late '80, '90's as a lot of Vans were.
As Max has pointed out it should have all the GTS goodies. The reality of the HJ Sandman is that is was a base Holden van with GTS options and a sticker kit.

The fact that it is one (a Sandman) and the price they now command it should be well worth while to be returned to it's factory state.