I have thought about this a great deal since E3, and I can only come to one conclusion: Yoshida-P didn't reveal it, because he couldn't. I believe that whatever the gun job ends up being, it will involve story elements from the expansion. The npc we get sent to from Limsa will like be in Ishgard or an as of yet unknown area. Though I have heard people mention gun blades this very well could be possible and make a great many of us squeal with delight, Yoshida does seem to like putting in "throwbacks". I would like to see that interview where he mentioned gun blades, I never remember actually reading that, just people saying that he said that.