If your actor is to be changing colors throughout its existence, then you will want them as instance fields (as you show above).
As an alternative, you can save the colors themselves and get the individual color parts when you need them; so, instead of saving 15 color part values, you are saving 5 colors from which you can retrieves those color part values from.
You may not even have to save the colors. It really depends on how you are using them.
You may, just for the sake of readability, rather go ahead and save all 15 color part values. However, the more you rely on your own coding, the more chance of an error creeping in. I, myself, would prefer to get the actual value from the color at the time I need it.