Do they work? There is quite of few times where I've had "Unmatched Ability" show up and the guns still fire.

When I was delay classing my AA gunners, they ended up being able to use up to like level 23 or so guns even though later guns were still classed as "gun." I'm fairly certain they can use guns up to the level they are classed *from* armament sailors.

They only work for level 12 armory weapons.

I forgot the exact level but they can use up to level 21 or 23 guns.