I've only ever seen pics from the toy, I'm pretty sure they never made the movie.
My guess is it was something from early costume design, which is why the toy has it, that was then abandoned in favour of using existing props. Unfortunately there is little in the way of behind the scenes material for us.
Not necessarily, the split between the kidney and ab plate should be 70 degrees, the ones from the OT (like this) are vertical.
My advice is to speak to your GML, it’s their ultimate decision, not ours.