Hi there! 👋
We actually made these assets specifically for Unity and don't really work with Godot :, so to be honest, I'm not entirely sure how materials are set up in that engine.
That said, all the 3D models share the exact same base texture, which is basically a single pixel color palette/strip 🎨.
As long as you assign that texture to the material of each mesh in Godot, everything should render just fine.
Hope you can get it working, and sorry for the inconvenience! 🙏