Yes, if you have a Smartgun, you get +2 Accuracy (usually factored in already) and +1/+2 to attack (depending whether you're using implanted Smartlink or just Eyeware). On top of that, Take Aim gives you +1 Accuracy AND +1 attack. So in total, you would have +3 Accuracy and +3 attack (assuming implant). So yes, there is are +3's in the equation.
The "argument" may have been in thinking that somehow, every time you Take Aim, you would add another +3 to the roll. Which is not the case, since Take Aim only builds a cumulative +1/+1 up to half your Willpower's worth. So a gunner with Willpower 4 can Take Aim twice at the most. Which would be +4 Accuracy and +4 attack, total.