Oops, doh, you're right. Still, it's probably, I dunno, 45%ish? Depending on how likely you think the preempter having the off-suit K is. 6♣ obv. is better and the logical thing for the E robot to do is bid 6♣ as an offer to play there over 4N... if you're going to 6 it can't really hurt to show the fit.