To the best of my knowledge, there has only been one 206B that was certified for IFR and that wasn't even a full IFR certification (it's the Bristow's one in the UK).
Problem with certifying the 206 is only one generator, no force trim and doesn't meet some of the handling requirements without a stabilization system.
It will, for all intents, forever remain a VFR machine - and people who try to fly the thing IFR or in very poor vis will continue to suffer the consequences.