Comic is read right-to-left.
Not counting Kanto, Unova is the only region where no old Pokemon could be found (save for the Pikachu billboard and Pikachu in Castelia) until either after you beat the initial storyline or if you got them in a trade. However, in BW2, you can find plenty of Pokemon from past generations.
That said, how did you feel about GF's decision to have only "new" Pokemon until after the storyline? Did you like it, hate it, or were ambivalent about it? Would you like future regions to have only new Pokemon until post-game?