Hi Wayne - welcome to the forums.
From what you're saying it sounds like a Sandman. The in-place wiring for the courtesy light means it's either a Sandman, Kingswood.
Since your Body plate indicates a Holden base model 8WM70 (not Kingswood) and you have an complete headlining strip I'd say you've got a winner.

Just a side note - it was possible to order courtesy lights on the base model, but you also have the headlining strip and other identifiers that would make it authentic.