Thanks for the info, the different colors are different lengths.
The current indicator rod is solid rust. But i did find the specs (page 55) n the 2012 catalog that states colors. Of course there are 2 versions of the SRK5 hub: W & N. Same specs. Same axle, old, same ratios. ??? For some reason the only difference is the smallest possible cog size. But fortunately both state purple indicators.