The guy you're asking about is supposed to be a praeco, a sort of public herald. This answer to a followup question on the use of gesture within Latin oratory should help I think (and certainly answers the followup question you've posted on here), as would many of the comments in that thread as a whole. I've only seen Rome once so I don't really remember the character much at all, so I can't say whether his gestures as a whole are attested, but definitely some of them are, as I mention in that thread--however, the praecones were not really orators but simply heralds, and I know of no text that attests that they actually spoke using the gestures of the Roman orator, although it's not totally insane to think that they might have

Followup question: he at times has advertisements in his announcements as well. For example, "The capitoline brotherhood of millers — true roman bread, for true romans" and other such things. Would this sort of thing really have been included?

I hope this doesn't sound stupid or ignorant, but could one draw conclusions that this type of hand gesturing while speaking directly lead to the stereotype of Italians using had gestures while they speak too?