It's not that the article didn't name an UB, it's that it's calling DiChiara 'street boss' when, to me, he's doing precisely the duties of an UB, ie being a conduit between the capos and the official.
A SB is acting on behalf of the official eg if incarcerated or not involved in the daily decisions. Neither of which the article mentions Bellamo. IE he's not incarcerated nor has he stepped back. So why the term SB instead of UB? Or as he's mentioned as consig, 'acting UB'.

But I never was too quick on the uptake.