There is a plastic/teflon cup under the ball in the joint. It is part of the A arm. I did not miss anything when taking it apart... If you look at a stock a arm the ball joint is part of the a arm.
I pre-heated the part as usual, and when I went to powdercoat it the cup was melted. I am sure you can powdercoat the a arms, but the question of the day is... How do you know if you melted the cup in there?? You won't know it, and your customer will never know it until it fails prematurely. So good luck with it, and I hope it works out for you.