From the looks of it, they 3D printed new housings that fit into the stock fog light housing to house the new LED pod lights. I'm pretty positive it is 3D printed by the giveaway of the black print lines/layers. So there's that route, OR another would be to get in there and fab up some sort of bracket mounting system based off either OEM or fabbed mounting points. But this route probably wont look as OEM+ and good as the overland concept because since the pod will be held in place using brackets there is bound to be gaps and open sections...You could fill those gaps with a mesh of some sorts to hide any voids, but that may not flow well with the OEM grille design...
I'm interested to see what you come up with if you decide to tackle this. You would really have to get creative and have some technical resources to do this the right way in order to make it look OEM+ like the overland concept... I wired LED light bars to my roof rack, but that was no where near as difficult as this project might be just due to trying to fit something that isn't OEM into an OEM location...