If you think about it, you can't have a sub bass and a very low-end kick without both clashing. You have two options, either pan one left and pan one right, which is not likely wanted; or remove the sub frequencies from one.
Audio-mixing is relative. An 808 kick that is missing a lot of its extreme lower end frequencies can still have a lot of bass due to the sub bass that is playing alongside. However, when you remove the sub bass, the kick could and likely will sound very thin.
So, the answer is yes. Simply, they both can't have sub-bass and one has to complement the other.