please notice, that under .net / RhinoCommon / C#
is R 255 G 165 B 0
and Rhino s color-chooser top-level Orange is a mathematical Orange
is R 255 G 127 B 0
if you use
_selColor this might help you to coordinate programmed colors and Rhino.
see also this old post:
the precise location of the color.txt is here