Nope, they are on the top like this:
Row 1: 600 HPS - 600 HPS - 600 HPS - 600 HPS
Row 2: 300 LED - 300 LED - 300 LED - 300 LED
Row 3: 600 HPS - 600 HPS - 600 HPS - 600 HPS
I use 4 Cali. Lightworks 440W models, but right now I took one of them out of the room for an upcoming LED test run and replaced it with two smaller off brands.
The 600 HPS are over 3 x 2.5 area... I might modify that to a 3 x 3 later, but don't mind the extra light.
The '440w' (300-340w) LED are over a 2 x 2.5 area... seems pretty good here, but I might also up them to either a 2 x 3 or 3 x 3 area.
The LED spectrum causes the plants to take in a little less food, but they still chunk out seemingly as well as under the HPS.
Not sure though if I want to spread them out more... gonna wait and see how they fare in a 3x3 area all on their own!