A reflex is a response to stimuli. We are exposed to gravity from the moment we are born to the day we die. It's a reference point.
When a baby or adult needs to bypass the structure of gravity, their body's are already saying, they need help. So yes, you might have an overactive or non-responsive primitive reflex. Anyone could agree with that visual observation. However, if the cause of this hyper or hypo response is due to a lack of a proper gravitational reaction, then your course of action is to enforce your gravitational reflex response first!