Factchecker concluded that the docs were produced and genuine:
http://www.factcheck.org/elections-2008/born_in_the_usa.html
Disclaimer: I have no idea how reliable factchecker is, lol.
As for the lawyers who brought the suit, I am not going to defer to their opinions. I have no idea whether they know diddly about any of this, but I do know there are all types of lawyers, and they are just as subject to being biased as anyone else. Until I have some reason to trust their opinions, I will go with my gut on this one.