I reckon that's it Steve. The Nova was definitely black first time out in Dec 1967, but Spinner Black's Camaro wasn't at that meeting.
As far as I recall, the Nova then went back to Australia, but was used seldom if at all until its' return to Bay Park, painted blue : I tend to agree with the Labour Weekend theory. By then the jig was up, the Nova was heavy and underbraked which Norm had offset first time out with piles of bravado and lashings of opposite lock. Next time out, and for the subsequent Dec '68 meeting, it seemed it was no longer much fun to be steering the old girl. Didn't stop Norm making a legion of fans with his thrilling driving and effervescent personality. Great days...