Search the Internet and nothing is black and white. I think you can get both appearance and also mix appearances. BUT, they are all " Hybrid" as this article said. http://www.voren.com/articles/hybrid-not-mutation/
有時見d金頭bb個頭好黑,有時又好金,佢哋係唔係hybrid只有個breeder自己知(or 連佢哋都會唔知)!