Mine are blue for the first 1/2 inch and then the are golden around the first bend. I like the look. One of the first things I look at on a bike are the pipes. If they aren't at least a little discolored, seems the bike spends too much time on the kick stand or the trailer.
I was at a poker run one time and a dude with a beautiful Harley was spoutin' off about "When I rode into Sturgis..."
I looked at his gleamingly clean, non-colored straight through pipes I called him on it. Yep, He trailered out there, stopped at his hotel 10 miles outside of Sturgis and took the bike off the trailer. The bike was a 2001? model (4 years old) and had a whopping 6000 miles on it.
I had a good chuckle over that.