Fuel heads are billet, they start as a solid chunk of aluminum, and then you machine away everything that isn't part of a cylinder head. Fuel heads come ported, if you wanted to grind on them after getting them I guess you could, but they are all the same (assuming same generation) so if you hurt one, you have a spare that matches it to go back on.
Pro Stock heads come raw, fresh out of the casting, they don't even have head bolt holes drilled. If you have never seen a raw casting, let's just say that if you didn't know it was a cylinder head, you would have a hard time recognizing it. They then get CNCed and most of the teams still do some "hand porting" when trying new things. If you find out that raising the floor .050 is a good thing, you can program that into the CNC for the next set.
Alan