The red spots are normal coloring for the golds. My hunch is that you are talking about something else, like grey patches near the dorsal fin that I can just make out in above photos?
Just an FYI. When I first got my red spot severum he had grey discoloring on him. Sort of like flaky skin or slime and it looked like he had dirty spots. I searched and asked questions, even medicated for costia ( see
http://www.gbasonline.org/disease_chart.htm )which did nothing. After all was said and done, the only thing that seemed plausible for my fish from talking with others was ammonia burns from poor shipping. The grey lasted I would say 6 months and then disappeared as the fish grew.
I hope this is helpful.