Each model has its own texture set so one material per model . Texture packing as per UE4 standard , Base color , Normal and Roughness , Metallic and AO are packed as : R = AO , G = Roughness , B = Metallic .

If you use this in Blender ( or any other render that uses OpenGL and Gloss instead of Roughness )  make sure to add inverted color ramps for Roughness and for the  G channel of the normal map .