As an aside, note how the kurios in Romans 14:9 is not rendered "Jehovah" as it was three times in the previous verse in the NWT, even tho its reference to the "kurios of the living and dead" is directly based on the preceding statements about "dying for the kurios and living for the kurios so that alive or dead we belong to the kurios"; this is because the kurios in v. 9 explicitly refers to Christ who "both died and came to life"
Actually it's even better than that, as v. 9 doesn't use kurios but the related verb kurieuo ("to be lord of") which echoes and refers back to the uses of kurios in the previous verses. For the sake of consistency the NWT should have forged a verb "to jehove" (over the living and the dead).
This passage, along with Romans 10, constitute irrefutable evidence that kurios was in the text right from the start, since the substitution of any other divine name breaks the very line of reasoning.