Jason could it be an XX7 but due to being an early HZ it may have been a mis-stamp / mistake?

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Found this on another site written by Byron, it is about a HX but may help

"In the above example it could never be an XU4 unless it was built for export to NZ as 18V is Sandman only in HX HOLDEN. Most XU4 HOLDEN wouldn't have the door switches either, or GTS dash or GTS wheels or headlining. XU4 probably wouldn't have carpet either."