In the good ole' days a manufacturer needed 100 cars that were identical to the car being entered to actually be registered in order to be allowed to compete. After all, it was a race for regular production cars.
I think that for Aussie manufactured cars the number was 250 cars, .. hopefully somebody can clarify.

One of the first posts refers to 'only' 100 being made with narrowed chassis rails in order to fit wider rims.

The question I ask myself is who would be spending the money to have this major structural modification done to 100 Datsun 1200 cars, & then never fit the wheels that such a modification would allow.

I have no doubt that someone, somewhere has probably done it, but 100 of them & never use them for their intended purpose? [Production racing at Bathurst]
The chances are pretty slim.