Speck Fitted case for the White iPhone 3gs?

So i've read about how the white iPhones i dont know if it makes a difference whether its the 3g or the 3gs but they've said to be changing colors of black and brown on the back because of a heat problem... i just purchased the white 3gs and a new case with a black rubber back, im kind of nervous to see the outcome.... do you think this iphone will heat up and take the black rubber back color? i hope the speck fitted case is made good enough so this wouldent happen.