The turn signals are different between the different headlight designs and are not interchangeable, but here the entire light assembly is being changed, so the turn signals have to match the headlight and its mount.
One of the differences between the designs is that the single plastic headlight/no foglight design is flatter/more vertical. The foglight type is more 'aero' with a significant difference in angle. I think this translates to simply being more forward at the bottom where they overhang the bumper, but am not sure and it's possible that the top is different so that the lights may not match the front edge of the hood. By this I don't mean matching the line of the center section, but whether the lights are behind or in front of the hood.