that is my guess.
I disagree, for two reasons. 1) This is the same temple that saved young Ben after Sayid shot him. There is no evidence to suggest that Jacob inhabited Ben to save him or become him. Ben is still Ben; the temple has special healing powers. 2) More importantly, the inhabiting of dead people is the ability of the Man in Black, not Jacob. Every appearance of a dead person 'resurrected' (Christian, Yemi, etc.) can now be read as actions of the Man in Black.
However, when Jacob saved Ben he was not dead himself. Now he is dead and if "the man in black" could dome back in another persons body (ie John Locke) then Jacob could come back in Sayids body and the war that Charles Whitemore told Locke about can begin. I odn't necessarily believe that evedry apperaence of a dead person is "the man in black" I believe that whom ever is the leader of the island (Jacob and now the man in black) has the ability to appear to people and take on the form of the smoke monster.