That's not an unreasonable definition of fact check, but it's not a universally held one, and it's irrelevant to the context of, say, live television shows. Considering the makeup of this 'panel of judges', the nature of the topic and the questions, and the context in which it appeared, I think it's more than acceptable to refer to the panel as being comprised of fact-checkers.
Either way, it's a distinction without difference. Checking the terms of a television debate on history with a group of professional historians is very rare, like Aroddo said, and the effort was quite laudable. Whether individuals refer to that group as a panel of judges or as a panel of fact-checkers means nothing. If they were judges, their opinions held more weight than almost any other such panel that Napolitano would encounter on television, and if they were fact-checkers, they were limited by their abilities of personal recall and preparation slightly more than they would have otherwise been.