Nige has hit the nail on the head, the expectation these days seems to be that owners expect a cheap powder coat to resemble a quality painted surface. I often get asked what the price would be to get the item painted, the reply is usually 'Howww much!'' The original cradles and other items were most probably coated quickly with a thin coat. Strangely, the wheels are turning and some now want the same crap authentic finish as per the 70's, I get strange looks when asking for it, and then asked how could they do it.
Like an ethanol petrol proof coating I saw recently, basically, ''The cap leaked on a non standard tank and my ethanol proof coating is damaged'' It was apparently applied by a professional sprayer who recommended it. Err, can't be ethanol proof then. I checked with the US manufacturer of the coating, I sent them a photo of the owners tank asking - could they please explain and was it ethanol gas proof, reply was a single word - No. Checked with the UK supplier of the stuff, they also said it was not not suitable for ethanol petrol.