I think the A139 mock-up in the photo was a planned utility version of the A129 attack helicopter, using its engines, rotor system, transmission, landing gear and tailboom and was given the "next number up" in the designation sequence at Agusta. I guess that design was abandoned early on and the "A139" designation was left without an airframe until the current A139/AW139 came along.
All these proposed designs that never quite make it off the drawing board or beyond the mock-up stage are often quite interesting.
500 Fan.