[Arran]

Getting back to the Hippo knobs, I think that if one of the hippo models had gold painted rings it's possible that someone may have used replacement knobs off of a 46-1201 or 48-1201 "Bing Crosby" as they are of the same design. I'm not sure about the hippo sets but the 'Bing Crosby's" originally came with gold rings painted around the perimeter of the knobs, though they are worn off on my Canadian built example.
Regards
Arran