I believe there are small changes that expert on the models could tell each model apart even in bare shell.

Obvious external change for wb is lack of rear side blinkers that earlier ones had. Up to about mid 74 hq had side vents behind doors and hq had a different cowl. Hj has different firewall to hx. These are just some, I'm sure there's others that might not want to be public knowledge for the body swappers