As said before if you haven't literally copied any of the buttons from the original you haven't copied it you are merely creating an imitation to the look of the original.
You could parallel this to the motorcycle world where Harley Davidson have been the kings of the chopper and cuisers for years only for the japs to release copies of the look in their bikes. What did HD do? Nothing but merely state that imitation is the best form of flattery.
Just my 2 penneth worth and let me have the skin now.