Well of course I won't blame the koreans when they have help available to them and take the given opportunity, I just dislike the narrative that paints the project as if it doesn't get a lot of help from foreign contractor, and it does, from lockheed martin. Source:
(this on in particular has a detailed timeline about the project and subjects that are involved in it)
If you're referencing the second block of KF-X with internal bay then sure, though it's decades away and who knows what will happen. If you're referencing the current state of the plane then no, it's not a 5th gen fighter, again not even the koreans would claim it to be the case.