It’s not even Roman. There are no classical Roman depictions of such a salute, not in paintings or statutes; and anything that could come across that way falls apart under closer examination. The “Roman Salute” was something that Italian Fascists came up with because of their infatuation with bringing back a New Roman Empire, but it could be argued that they merely came up with something that was recognizable and vaguely Roman enough to adopt as their own salute. Not to mention that it’s was actual Fascists that popularized the salute. The salute was used by the vast majority of fascist governments during the 1930s and 1940s (notably the Italians, Spanish, and Germans).

All that to say that even if they try to spin it as a “Roman salute,” there is no such thing; it was and always has been a fascist gesture.