A lot of the keys were taken out so they took the achievement out completely. Probably should have been made a feat (scholo key in classic? Need I say more) but, oh well.
well the same thing happened with master of arms and knucklesandwich achieve. they eventually ended up as FoS. they weren't there right away after the patch dropped. here's hoping it will be the same with keymaster
I seem to remember getting Master of Arms and Knucklesandwich immediately on 4.0.1; even still I'd be surprised if Keymaster didn't eventually come back as a FOS.