That is about right, except I think Peter Arcadipane designed them for the HG at first. I dont know why GMH advertised them only for the HQ Kingswood ute though, seems strange. I've tried to locate that double sided ute in the records but I can't find it, it is obviously a 1971 build by the lack of headrests.
I think the De-van with the chicken on it actually started as the De-van and later got painted white and had the Chicken decals added.