Once it's pitted, it's pitted. Now, for collector value, the price goes way down. For users, it depends on how badly the piece is pitted. Some mild pitting will not affect how the piece cooks. If mild enough, enough seasoning may even even it out. However, if the thing looks like the surface of the moon with big gaping craters, no amount of seasoning will help and food will get stuck in it.
If it's on the outside bottom, like sometimes happened with old gas stoves, that has no effect on how good it cooks. Has almost no value, but it still cooks well.
