I would expect that Sikorsky are following the Carson rebuild model which replaces the main frames to achieve zero life.
Of course the Carson rebuilds invovled entirely civ registered S61s, both long and short fuselage variants.
His plans for a re-engining with different engines were thought provoking and along with the new aerodynamic mods would have achieved performance broadly better than the S92 at a much lower price of course - or so it was claimed - so I would be suprised if they see the light of day in the new Sikorsky contract - anyone know?
Cheers