Vorton projectors are not turrets from a weapon-class perspective (they use turret mounting points on a hull, but are not otherwise classed as turrets); they are Small Upwell weapons. As such, turret buffs do not apply to them. This is why they have separate skill entries as well.
Thanks, I suspected as much but couldn’t find anything at the time I posted which definitively stated that.
Digging around in Pyfa a bit more I note that the booster effects the Surgical Strike skill bonus and that Vorton projectors themselves are not affected by that skill so that all makes sense now.