Do these tags mean its a HJ sandman panelvan?

[Innuendo]

While mistakes could of happened it is unlikely.
Should you feel a car is a likely miss stamped Sandman you need to find the documented proof I.E: Sales receipt, production sheet or purchase order.
Without the proof it is not a Sandman - Simple.

[Sandman]

While mistakes could of happened it is unlikely.

Have to disagree with you there when it comes to Acacia Ridge..... They stuffed up often with plate stampings. I had a 308 4sp HX Monaro Brisbane built... Vin had a T for 308 but other plate was stamped L32 M21....

James had a HJ XX7 that was stamped as a 3 seater and then over stamped with a 2.

I would say there are quite a few Brisbane built Sandmans that missed getting XX7 stamped, particularly HQ and early HJ.... as you say though they will never be accepted as a genuine Sandman unless you are lucky enough to find the build sheet.