Bill and Kings are friends, from school, so I think Kings would have gotten to know her before the switch and all. I think it'd be entertaining if it took them a few months or more to figure out they both were off it (lols the conversations), but then it'd be interesting if they did both know.
Kings has probably kept tabs on the people he knew to be in the DA. he wouldn't breath a word betraying himself unless he was 100% sure, but they totally can have figured it out. YAY interaction. Kings is excited for that.