I dont think he is texturing??? I think it is just the face he has altered hasnt come up with the shader assigned to it...it has happened to me occasionally...on imported objects. As stwert said you dont have to UV....its just not recognising its assigned material. I wouldnt worry about it if you are just modelling or fixing the model up. However ONCE you have finished modelling..as Jay said, you will then have to UV map the car...every bit...so when you do assign textures/materials to it they will be properly arranged.

If you have the dough, grab one of Jays or Kurts tuts, the UV mapping process is spelt out very well and it isnt hard, just a lot of work. You dont need the whole tut if you cant afford it, just the texturing parts.

Cheers bullet