That is how the ceiling was when we got it. Actually, we're redoing the walls and ceiling in mahogany veneer, the ceiling was repainted several times by previous owners. We would like to do something really sleek and sexy and up to date with the fixtures, but where do you get the new white plastic ones? That may be a good enough solution.
Try Andy or any other Airstream parts supplier. Actually I got mine off ebay a few years ago. Price is reasonable wherever you purchase, and they are authentic. Plus, you can use these when dry camping. Other fixtures may not be compatible with your marine battery power.