The Bar in question resists torque and also acts as a suspension location device. The following section seems to apply.

GCR 9.1.3.D.5.c.2
On those cars where an anti-roll bar also acts as a suspension locating device, the diameter of the bar may be changed. Barr attachment and pivot points on the chassis and control arms shall remain as stock, except as provided for in these Rules, Section D.5.d.1., and 3.
Those two sections deal with camber adjustment.

It seem to me that if the people who wrote this section did not want a control arm such at the Rx7’s to be replaceable the above paragraph would not exist.
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I believe this applies to cars like the original Ford Capri which had a front anti-roll bar that is also one of locating points for the front suspension. Think of an RX7 with the anti-roll bar and the strut rod as one in the same and you have a Capri front end.