That is one way to do it, but depending on how you configure it when you create it there might be an unnecessary gpu resync performed internally. The best way to do that is via SetMeshCollisionSection() and then ClearMeshCollisionSection() or ClearAllMeshCollisionSections()
You can see more about those here… https://github.com//UE4RuntimeMeshComponent/blob/master/Source/RuntimeMeshComponent/Public/RuntimeMeshComponent.h#L1147-L1156