Usually some sort of crossover is beneficial (generally it's cited that the offset pulse-trains help carry each other downstream, thus increasing average exhaust velocity and scavenging, which are key). Sometimes that's an H-pipe or an X-pipe, and sometimes it's more of a Y-pipe into a short fat section before splitting out again. There are subtle pros and cons to each method, but there's no point quibbling about what is or isn't "true dual" really. You probably don't want a completely isolated pair of exhaust systems on the car.

My exhaust hits the crossmember... It didn't at first, but it's been on the car for a few month now, and now it does...