Based on the fact that biology text books are still being used today that have Ernst Haeckel’s forged embryo drawings and pictures of dead peppered moths glued to trees, I doubt such a discovery would change the books any time soon.
you know, something tells me this is false. I definitely don't remember seeing anything drawn by Haekel in my bio textbook (Campbell, standard issue apparently, in colleges).
I also don't remember a single picture of those moths. Were both talked about? Sure--only to say that Haekel was wrong and that the moths provide a good example of natural selection working on traits.
If you have any issues with these two, we have whole threads devoted to them. try looking them up with the search function.
And yes, they would be updated. Why? Even my history book gets updated--I've got the '06 version, but they already have an '07. And nothing happened that would significantly alter an introduction to western civ. in the last year. If something did happen, it would be included without a doubt. I was using an 05 (maybe an 04) Campbell's Bio book when I took my bio class. They now have an '06 or '07 edition. If something earth-shattering for evolution (or evolutionary history) happened, it would be included.