I don't think it is painted
Athough it does look painted.
When Hobart divested the KitchenAid division they started to muck around with the classic look of the K-5A. Around that time the "all-white" look for home kitchens was popular and I think because they went to the expense and trouble of using white plastic for the knobs and accessory plug, they were shooting for that look.
I still have and use my KitchenAid K-5A that I bought from my employer Elgot on 70th Street, in 1977. It was up in a storage attic in its NFS box and I couldn't resist it. It did time in my Parents' home for about 20 years and then I used it in my work. 40 years and still going mostly because I have this wonderful guy, Myer's Electric on Whalley Avenue in New Haven. He has repaired it once and I have told him that he can never retire.
I use it multiple times every week for making bread, cakes, desserts, dim sum doughs, grinding meat, kneading pasta dough and sheeting/cutting pasta. I intend to have it outlive me.
BTW, I still have my Grandmother's K-3B; it still works but I don't use it. It is more than 68 years old.