If you’re using clinical definitions, I’d say probably not. To say that most Mafia members are sociopaths would mean that the selection criteria for the Mafia would involve psychological testing, or that the skillset required by the mafia is uniquely suited to clinical sociopaths.
I do not think either of these things is true. Thus, mafia attracts sociopaths at the same rate as any other career path that attracts sociopaths. Which is probably not zero but also probably not huge either.