Not sure about the thinner top deck, but using the standard thickness top deck and chassis, I am able to use the Orion 3600 and 3800 LiPo. I did have to grind away one screw hole on the rear battery side bulkhead. Is the Orion 2400 taller than the 3600 and 3800s?
Regardless, the distance between the chassis and top deck is the same, since the height of the bulkhead is the same. It doesn't matter what thickness the top deck is.