GMH normally distinguish between bench and bucket seats with trim codes on pleb spec vehicles, but stopped at HJ release then started to do it again during 1975, then stopped again at HZ release. So on a base spec HZ with bench seat there isn't much difference between HX 67W and HZ 67V, both are called brown. Same with base spec HX with buckets (67V) and HZ (67V). However 67V on Kingswood (tan) is a different vinyl to base spec 67V.

GV4 is 3.36.