Depends on how you have switched the A/T off. If you have switched them off with the A/T Arm switch on the AFDS pressing To/Ga will not wake up the autopilot.
However having disconnected the A/T with the disconnect on the throttles themselves pressing To/Ga will give you To/Ga thrust and also F/D guidance.
You are required to press To/Ga on a manual windshear go around because you want Windshear Guidance from the Flight Director (F/D). Pitch to 15Deg initially and then further up with the F/D (as per the QRH drill)