If it has been introduced I would expect them to announce it soon.
Referring to the list provided by
Siebrand, it would appear that
extra-legroom seats follow the standard rules (free for Platinum, discount for Gold & Silver). Does this also apply to Economy Comfort seats, as on long-haul the seating products have different names?
To be honest I am quite surprised that this would indeed be the case, they have not adopted a more generous policy a la Delta, where they on intra-US flights offer EC to Gold members as well.
But I am sure KLM has done their research and I am sure we are all eagerly awaiting a press-release