Is there proof that this greeblie was in the movie? Keep in mind that people who restore the props in the archives sometimes don't get things correct. I believe it was Don Beis who used to run the archive building years ago and he mentioned on the rpf in regard to the landspeeder how he had to replace some of the missing greeblies, gear shifter, steering wheel, etc. The new greeblies aren't the same as the original. This has happened on a lot of the props over the years and could be the case for this costume. The suit that used to be on tour didn't have greeblies on the detonator. Maybe they fell off, who knows but someone could have grabbed this greeblie from somewhere in the archives and slapped it on there just for creating these 3D rotational features on the bluray.
That's speculation of course but so is assuming it was in the film. I always felt the red rectangle on the top of the tank may have been used too so it should be an "acceptable" detail but it's not accepted in the lancer requirements. If this piece isn't proven to be in the film then it shouldn't be a lancer requirement either.
I'm happy to change my way of thinking, I just want to see something tangible to back it up
Thanks and happy holidays