^^ to me, those don't look like they've been dyed, as you can still see beautiful color variation on both. gorgeous bags btw!!
i've seen pics of dyed bbags on this forum (there was a thread awhile ago about a dyed 05 turquoise work, and you could just tell it was dyed b/c the color looked like it was PAINTED on and the dye was actually flaking off). if you do a search, you should also be able to find other threads where people have dyed their bbags b/c they were so worn out or they just wanted a different color.