Did everyone see the story about the rear spoiler protest on an ITA RX-7?

I've seen this car many times, but it never occurred to me to comment on the spoiler.

The owner, Chuck Koos, used the GCR section 9.1.3.8.b as justification for the spoiler. I can see why, although generally, it seems to be more about FRONT spoilers than rear.

Do you all think that there is an intent to allow aftermarket rear spoilers in IT? Does that allowance need to be clarified?