Noboru’s cold reaction to Ryuji and the gift contrasts with his obvious enthusiasm for Ryuji’s adventures (as proven by the stamps). Again, even though Noboru views himself as stoic and sophisticated, he is actually still quite immature. In fact, he’s playing a part even more than Ryuji. Still, Ryuji seems phony to him because he now acts like an ordinary family man, not an intrepid sailor. And the crocodile seems phony because it’s just stuffed skin. This recalls how, after Noboru killed the kitten, the chief suggested that its organs represented reality, while its skin was meaningless.