Are you 100% sure that they're HQ? No side vents so extremely late HQ using HJ shells. More likely HJ, unless you know otherwise.
Nothing to say that these are factory either. Could simply be the first time offered by Holden. I.E: Early HJ
Whatever the case, many variations of side panel sizes exist so it is unlikely you pull glass from one and fit into another (unless the same supplier).

I guess we are looking for GMH paper proof, and lets face it. If Holden was offering this option on HQ the price would have been horrific!