Those lights on the side actually aren't fog lights. They're turn lights. They come on with the turn signal (when clicked all the way, but not when just held for a lane change) to illuminate the road you're turning onto.
The actual fog lights are in the same housing as the headlights.
7th gen bumper would definitely not work. The designs are very different...particularly, look at the hood/bumper seam and the way the 7th gen bumper wraps over the headlights.
But there are other options. The later 6th gen ('07 and '08) used a different bumper from yours, but you have to change out your headlights and hood as well.

On this bumper, the lower lights are indeed fog lights, not turn lights.
Here's a thread on the conversion:
04-to-07-maxima-front-end-conversion-t362906.html
Or there are aftermarket options for the 6th gen.