This is something I endlessly harp about, since I had family that got beaten up by the Blackshirts and I spend a lot of time wargaming, reading up on, and even roleplaying in the era.

And the first thing you see is that the Fascists were QUITE open that they were socialists, and even more open about how their philosophies/policies evolved from socialism. Hell, Mussolini even has a subsection on The Doctrine of Fascism dedicated to it.