If I get my radiator boiled out at a radiator shop, will that process also degrease it enough to paint or will it require additional cleaning? To come closest to original, does everything get painted gloss black? Leave cooling line fittings unpainted?

The chemicals many shops use to clean radiators should clean the copper enough for paint. I have always used Krylon Semi Flat black, but I am not a resto guy. I just like the look.