Terry although i'm happy to be wrong I don't believe the reason they had Belmont, HOLDEN or Kingsowod badges on HQ and HJ Sandmans was because the guards had holes in them. I believe it is because they were a Belmont or Kingswood. SS didn't have holes at all but it was a different lux level to a Belmont, GTS sedan did for both Monaro and GTS badges but it was meant to be a different lux level to the Kingswood it was tagged as. I think some GTS coupes had bugger all badges too.

HX and HZ Sandman were meant to be seen as a separate model/lux level like you say, hence why they lost the HOLDEN badge off the tailgate. Plus they were no longer the same basic lux level as their base vehicle as the Sandman packages included lux level upgrade equipment to basically Kingswood spec (chrome, trim, stainless etc).