From what Nicole Perlman, who worked on an earlier version of the script, has to say in the following video, it seems a done deal.
Perlman says that because of all the buzz surrounding Guardians of the Galaxy as well as box office expect ions, there will be a Guardians of the Galaxy 2.
She is then asked if she will be a part of it with Perlman stating no, but says James Gunn would be both directing and writing the sequel.
James Gunn previously stated that if Guardians of the Galaxy is a smash hit, he will be back to direct the sequel, but if it just does okay, he is considering other offers.
I seems Perlman states Marvel is expecting Guardians of the Galaxy to be a success, which means Gunn will be back for a second movie.
It's also been stated that James Gunn is up to direct The Avengers 3.
"Guardians of the Galaxy" has an August 1, 2014 release.
For news, images and more head on over to the Cosmic Book News Guardians of the Galaxy Movie Hub.