Yes all HQ bodies out of the Elizabeth BAP (body assembly plant) had an Elizabeth BODY tag with an Elizabeth body number on it, even the hard trimmed and painted bodies exported to be assembled at Mosman Park, Dandenong, Pagewood or Acacia Ridge. The number changed over time, for example from the start of HK it was a cumulative number for the model, so you'd have 1-A, 2-A, 3-A etc for all models, so there would be a 1-A for a HK KIngswood sedan (80369) and a 1-A for a HK Belmont utility (80180) etc. It stayed this way for a time resetting at HT, HG and HQ and also a different sequence for LC and LJ. During HQ and LJ (around May 1973) it changed to a single cumulative Elizabeth body plant number which I think started at the beginning of HQ. It remained that way until August 1977 when the body number became the numerical part of the PSN in alignment with Dandenong, Pagewood and Acacia Ridge processes.

Note that it was only stamped up until some time in HJ, around November 1975. After that it was embossed (from behind) like the rest of the tags.

No. Once they started using the sequential body number around 5/73 on the body tag they stopped using it on the cowl panel.