Could this be a sandman - Chassis swap

[playwme]

As an example

What I beleive is when a vehicle HZ van is crashedchassis bent and repaired replace chassis using a part from another vehicle HQ ute, that partHQ Ute chassis becomes part of the repaired vehicleHZ Van.
The numbers/letters stamped on that partHQ Ute Chassis now become the identifier for the repaired vehicleHZ Van. Just as my rego paper show.

Maybe it's because it's late and the bloody baby is awake and wants to play, but that looks like what Oz was saying.