I looked at the wiki page for KMS-4 and it seems the only person who is suggesting it might be an EMP weapon is himself. In this article he makes it sound like

I looked at the wiki page for KMS-4 and it seems the only person who is suggesting it might be an EMP weapon is himself. In this article he makes it sound like it's a definitive, known fact. In the wikipedia page it's more like he's warning about the potential for such weapons.