I recently spoke to muscle car parts in Sydney, (they usually have a stand at all holden day, with Torana & HQ repro panels) & they said they don't have any plans to do HZ style guards at this time

Im sure there was repro gts guards done for HZs a while ago, (I presume the same supplier that did the twin h/l aprons with the rolled area above the grille, copied from the single h/l apron). I wonder if they still have the die stored somewhere?