This, from the description, strikes me as more than a little slanderous of the Epicureans, if not of the statue
"By the late first century BC, the Epicurean attainment of pleasure applied mostly to eating and drinking, and the principle of moderation was less significant, as is evident in the proudly displayed fat belly and uninhibited self-satisfied demeanor of this portrait"
EDIT: OK I was at lunch when I typed that and I was far too mild. It's not "more than a little slanderous" it's absolute BS!
So "the Epiurean attainment of pleasure applied mostly to eating and drinking, did it??????? I guess that's why Epicurus churned out all those books on natural philosophy!
Well it/he/she is probably right about "the principle of moderation" being "less significant" because "moderation" is largely BS too! Epicurus teaches focusing on a goal and seeking to attain it, not "moderating" either in goal or in method. Leave the moderation to Aristotle and his "golden mean" BS!
OK as to "fat belly" so maybe that is consistent with Horace after the civil war was over. I will not presume that Horace had a fat belly when he was fighting on the side of Cassius and Brutus, but if he did then he quickly saw how disadvantageous a fat belly can be at times, and he wasn't devoted to it in every situation.
As to his"self-satisfied demeanor" -- NO ONE can hold a candle to the arrogance of a Platonist or a Stoic! If that would be the test and this image is "self-satisfied" then this must be a spitting image Socrates or Plato or Zeno the Stoic!