I use that 3d cafe tutorials they are quite useful...
now i don't think you can -..cause .mat files are just made for 3dSmax and it doesn't have nothing to do with script, cause a .mat file is not only 1 material, and they aren't shader (i think):
So: this is a .mat file and there are some materials made by me...
So as you can see there is nothings with script..so i think you can't "copy the script" to use it with 3DGS
You can use shaders though.