Technically, there is a VIN rule, and if the VIN IDs the car to be a certain model, (and that model isn't on the spec line you're claiming) some (prick) body could protest you and win.........even if the chassis are exactly the same.

The VIN rule was left in because there was a fear that somewhere out there there is a Bobcat XK type R that has an identical looking chassis to the Bobcat XK, but in reality there are significant differences hidden deep, and that unscrupulous types would pull a switcheroo.

It was hotly debated within the ITAC. (Interestingly, the person who wrote the request to remove the VIN rule is active on this board, and is known to be rather conservative with such things)