No support.
It doesn't make sense to enable a feature like this for a selective number of game modes when the game news channel can prove that a player of any game mode authentically obtained an item. At least for announced drops. This would provide an unfair advantage to the game modes mentioned despite any player being able to demonstrate valid proof that they obtained a drop legitimately. Yet they would be forced to regrind the same drop if they wanted to fill the slot again just because of their game mode.
I can definitely see where you're coming from. Ideally, if it were feasible, it should be available to all ironmen, but the fact that It's not available to some game modes because of the questionable integrity of other game modes doesn't seem completely fair either. It's a preventative measure for some games modes and, as a result, the other ones are getting screwed over.