Well, just as with Light's warning, this isn't the original version. The part about humans interfering with Repliroid evolution would not have been there to begin with. I can't find the original, though. Maybe it has the part about Cain building Sigma.
There are some other odd points, too, besides fossils from the Middle Ages.^^; In only one hundred years, how could Light's lab get buried several meters deep, unless it was built underground in the first place? Was X so dangerous Light worked in a bunker? What's been powering it all these years? (Can't be solar energy this time!) And isn't 14m x 8m large for a "capsule"?
This version is probably the one people are citing when they say the term Repliroid applies only to robots built based on X. By this interpretation, X and Zero aren't Repliroids, because X isn't based on himself and we have no idea what Zero's based on (unless it's Roll^^). But I know I've seen a simpler explanation in another source book, which just said Repliroids are robots that think like humans. And if so, X and Zero do count. But it goes to show even the definitions can change from one version to another.