Everyone but me seems to be gaga over Turnbull's case colors. He gets a lot of press, and because of that is now considered to be the premier expert and foremost authority on authentic case coloring.
I think that his Colt SA colors are excellent and authentic, but believe he's off on his Winchester, Marlin, and Sharps colors - way too bright, IMO. The colors on your Quig. look just like the original colors on a like-new 1874 Sharps I've had the pleasure to examine closely. Colors can fade in sunlight, but won't when properly stored away.
Don Menk at Color Case Company in New Springfield, Ohio, is the best at this work, IMO.