The elusive role of molecular reorganization in the growth of ordered organic multilayers using the Langmuir-Blodgett technique has been investigated with x-ray and neutron reflectivity, and atomic force microscopy. Use of deuterated tails as markers directly shows that molecules get attached to the substrate in asymmetric configuration but, apart from the first layer, reorient themselves to a symmetric configuration. An exchange of molecules between first and second layers could also be detected. Thickness remains unchanged between second and third monolayer deposition but density is doubled.