pack colors, the 3.1 rule question

I added the rule sometime in the last week. Older packs are grandfathered in and do not need to change their colors; we would have notified them if they needed to. It was not consistently enforced in the past, which is my fault!

Question then, I got a pack concept greenlit with its existing colors just earlier this month. Obviously the pack doesn't exist yet but it is greenlit with its existing colors; should I change them if they were below the standard? Or is the concept still valid with the colors it got accepted with?