A Supreme Court Chief Justice is certainly not going to get into a public argument with a newspaper about statistics that were mentioned during oral argument. He'll likely say nothing about this at least until the opinion phase, unless he decides he was wrong and wishes to issue an apology (unlikely).
At the opinion phase, IF he writes the opinion (or a concurrence/dissent), and IF he still feels that the Mass. point is sufficiently important to his argument to include _in the written opinion_, then, yes, he would provide some kind of reference or citation. However, he is perfectly free to completely ignore the line of argument he was making at oral argument, in which case it's unlikely he would mention it at all. And if somebody else writes the opinion, then it's unlikely that person will mention it, unless it's somebody on the left wing of the court, when they might very well mention Massachusetts snarkily (but without explicitly referencing Roberts) as an in joke.