To accept this prediction, you need to be in the party that believes the Losties will travel back in time again before the series ends. Evidence for this, as many of you know, includes things such as Adam and Even themselves, unless you believe Rose and Bernard are already them since the last time shift, and even more convincing evidence is the infamous time-shift-shooting-other-canoe from the perspective of Locke, Juliet, Sawyer, Miles, etc.
So, I for one believe they will travel back in time before the show ends to clear up some of these things...one of them being Adam and Eve's true identities.
Now for the new idea: What if during a time travel incident, some Losties see that it is infact Rose and Bernard whon are Adam and Eve but they are without the stones. Someone, obviously someone with major knowledge of the storyline at this point, puts the stones on Rose and Bernard during this flash backwards, or later in the episode...only they put the White rock on Rose and black rock on Bernard indicating to the other survivors that, in fact, Flocke is the white or Good person (maybe Jacob) and the seemingly good Jacob is the real dark force or MIB.
I know some people have thought that MIB is the good guy and Jacob is the bad guy and we've been led astray...this theory just ties together some inevitable (in my opinion) time travel, the answer to Adam and Eve, Rose and Bernard, the black and white rocks, and who will end up being good and bad.