So, as it stands, you can take a 1989 Bumblebee Sprint, and if all are on the same spec line (which covers the 87 to 91s), you can use the 88 transmission which has better ratios, the 90 injection system which made better midreange torque and power, and the 91 hood and bumper which were lighter and more aero.

Those parts come from Bumplebee Sprint, GTs, STs and RTs.
But none were found on the same car, ever.

To me, that's making a model, as I see the model as being defined by the last two letters. heck the dealer charged more for the GTs than it did for the GLs....and the equipment was different. That is, to my eye, a "model"

But, yea the ITAC and the CRB before it, has considered that rule differently and classed accordingly.

As it stands, it's all about if they got it right at the start with the classing