HQ only had the Sandman badge in the horn cap.... HJ-HX are the same as HQ but blank, no badge.... HZ are a different shaped horn pad with the Holden Lion circular badge in the middle.

HQ GTS wheel center metal spokes are 5mm thick, these changed in later models to 3mm thick but it is unknown at this time when the change occured, I haven't checked parts manuals to see if the part numbers change..... may have to take a looksee.