The time consuming and hard part is filling in all the pits with base metal. And even then there's no way to know how good it will come out, or if it will come out.

$600-$700 doesn't so bad to me if you have assurances that it will come out looking great. Even a decent used panel with very minor pitting has to run in the $300-$500...if you can find one. If the "restorer" burnishes out sharp edges or other details in the process, you've effectively got nothing for your $$. I would think a part that large just to do the final finish plating would run approx $200.