Sorry if this is a stupid question but can someone please explain why they would modify an existing filming model? Add extra greeblies, panels, etc. would it have been for instances where they've had to cover added extra lighting and wiring? I've probably answered my own question but to start adding tiny little bits like tank wheels and tracks when it will hardly be seen seems a bit daft? Perhaps a new member of the props crew has decided to leave his/her mark? If that's the case I'd probably have done the same hehe