Yes, but that's not part of the ability "Single Weapon Style". You get +12 ACC automatically when using a single one handed weapon - like in PoE.
Since dual wielding has been nerfed to 30% speed instead of 50% it's ok now. For example with a single rapier + modal you can reliably crit even foes with high defenses. Crits have 1.5 times the PEN, so it can be very effective against tough enemies.