機動戦士ガンダム 逆襲のシャア ベルトーチカ・チルドレン (角川スニーカー文庫) (Japanese Edition)

If the interview you're talking about is the 2018 Forbes one, he didn't actually say that. What he did say was that Sazabi was the first design from CCA he made, since everything had to be done "before the animation production commenced.". The "were done much later" part about Hi-Nu and Nightingale seems to be related to the movie's production. Also if you see the Mercari or the Amazon listings people posted here, everything seems to point that yes, this proto-hi-nu (it was still called Nu Gundam nonetheless) was in the first print of the novel. The actual Hi-Nu design tho was only made on one 1990's issue of Hobby Japan.