Well that's the debate, and my concern:
First, it appears that if you have a skill at level zero or greater then you have all its contained knowledges at atleast level zero. Thus if you have Fighter-0 then you also have Battledress-0 ... something many us balk at.
Second (and on this point there is disagreement on how to interpret the text) if you gain a Knowledge, do you gain the underlying skill? The text says
Which mvdwege takes as meaning you can have the Knowledge without having the skill. Thus the default Turrets-0 would not confer Gunner-0.
However, the text also says
Followed by ...
So you haven't acquired the skill, just knowledges. Yet you still have Skill-0.
Which would seem contradictory but actually I think that's just because the first quote is ambiguous. It's NOT contradictory if ...
So Turrets-0 would confer Gunner-0, which (again) many us balk at.
Additionally, if Gunner-0 implies Turret-0 and Turret-0 confers Gunner-0 then the text should say Gunner-0 ... if that is what was intended. (Or maybe it was supposed to be Turret-1?)
I'm leaning towards dropping Turret from the default list of skills.