Silverbolt has always been an off white, Pulse. Which doesn't explain why the Classics one is light blue..

As for why he _isn't_ white, kup... apparently Hasbro try to avoid having two toys of the same colour in the same class on sale side by side. Since Powerbreast is white... Silverbolt gets blue. The irony is that in their quest to create a more "realistic" Powerbreast, they've made Silverbolt _less_ realistic. And messed up both tributes. Sigh.