Gaston Glock didn't sell the incorporation.
Gaston Glock designed the generation 4, along with the 3rd generation models. The only difference in the generation 4 model is that of a newer texture of the Gen 4 which is made up of polymids in which Glock calls them. Multiple back-straps, and a new recoil system aside from the newer magazine release.
The matte finish is a great new add to the new generation. It is much easier to grip but it can be scratched much easier than the older models.