Yes, it can be any color under the sun. It's your house.

But, no...if you want the cupola to be harmonious, make it match your house trim.

Good luck on your decision.

Given my druthers, I'd either have it match the house siding proper or the trim (assuming different). Up to you. But probably whichever is the lighter color.

I always wanted one of those, but they'd look really bad on a log home!