What is actually a Sandman and which isn't for NZ transport would be similar to asking a kid which end of a sausage is the pointy end! The info they have would depend upon many factors:

a) That when the car was sold new in NZ that it was recorded as a Sandman.
b) That when it was bought over as a dealer swap that it was recorded as a Sandman.
c) That when the car came over as a used car that it was even known to be a Sandman.
d) That when any of the above changed hands or were subsequently registered that they were noted as a Sandman.
e) That when any van or ute or even replica Sandman was registered it was recorded as a Sandman.
f) Similar circumstances to any of the above.

When you see how many Sandmans sold new over here do not mention Sandman on the VID certificate, and how many registered are simple recorded as a ute or van. Then how many people think that any van is a Sandman or any ute or van with stripes is a Sandman you can see how it would be hard to believe those figures.