I'm confused on the role of gunners. Are they entirely optional if you have the right programs loaded into the computer? Is their only benefit interacting with the gunnery interact program and adding modifiers to starship combat?
PS: This is for book 2 starship combat..
In a word, no.
With the usual caveats that YTU can be whatever you want and this applies only to CT and primarily LBB1-3 and that I may have missed something even after all these years.
The preponderance of evidence is overwhelmingly clear that the intent is that a sophont is required for each turret, and they need a minimum skill of Gunnery-1. I grant the actual wording of the rules may have been clearer to make that intent more obvious. My interpretation follows each brief note in italics...
Book 1 - p19 Gunnery - "qualifies... to operate"
without the skill you may not operate ship and vehicle weapons
Book 2 - p9 Mail... - "gunner must be a part of the crew"
perhaps just a legal requirement but regardless of the reason it is a requirement
Book 2 - p16 Gunner - "armed small craft require a gunner... "
while later clarified that the Pilot may fire the weapon it is done at a -1 and the Pilot is still required to fire it and have at least Gunnery-1 (and fires it at skill minus 1)
Book 2 - p16 Gunner - "may be omitted if there is no immediate major threat..."
so only if you won't need to use the weapons will you not need a Gunner
Book 2 - p19-20 Ships - each example, seven ships in total, show that Gunners are added if weapons are added, and the ship with actual weapons installed includes Gunners in the crew
pretty clear
Book 2 - p23 Crew - "Gunner - As required"
which seems well implied to mean if you intend to fire your weapons
Book 2 - p27 Combat - "indicate the expertise of the gunner manning the turret"
another pretty clear indication that each turret to be fired requires an actual sophont in the seat
Book 3 - 22 Vehicles - "ATV... crew of 3... one with gunnery skill"
to show the application of the skill again and requirement of the sophont
And finally the computer programs, not required for actually firing but advantageous (small craft at least may fire weapons without a computer but do so at -1 to hit and cannot add gunner skill) all but one of eight imply the need for a gunner, and one is specifically for a gunner. The exception, and it is clear that it is an exception, is Anti-Missile and all it can do is fire at missiles that are about to hit the defending ship. It does not even require the Target program. This clearly indicates that Anti-Missile is completely under computer control AND that the Target program is designed to be used under sophont control. The upshot (if you'll pardon a small pun) of this is that Gunnery skill is likely a computer interface type skill, not an aiming skill. This is reinforced by the Gunner Interact program. You get to add your Gunnery skill when using the Interact program and not without it.
Depending on how you want to count the above you could have over 20 arguments for the case that gunners are required to fire vehicle, small craft, and large ship weapons in anger. And only 1 argument that gunners are not needed and then only to fire in self defense at a clear threat from a specific type of weapon, missiles.
That's my take on it anyway but to borrow a sentiment I hold dear, it's your game, play it how you want to, and have fun!
