This is a low-poly asset originally created as a game mod. All game-specific objects have been removed, so this model is completely original. The original UV maps were only a few pixels X, Y, and flat colors. If you have other intentions for textures other than what ships with the model, you will have to unwrap them to your liking. I have removed the LOD features for Sketchfab, and you are welcome to recreate these to your liking using, for instance, Blender’s decimate features.