Ah, that's right. Forgot about those. But they're fossils from the previous generations, so I think maybe only after you get the National Dex? XD

Oh, and about that Roserade and Mr Mime examples I gave earlier. Apparently, there are some...requirements?
http://www.serebii.net/diamondpearl/breed.shtml
...but most Pre-Evos are available in the wild anyway~