I've got an MS290 with about 25 hours on it that I'll be selling on evilbay pretty soon. A $9 can of Stihl factory gray/white paint will increase the sale price by an easy $30-$50 over a beat-up bar. We laid the best side of the old bar across our scanner and scanned the "Stihl Farm Boss" words/logo, too, and my graphic artist wife cleaned that up and is cutting out a stencil so once the bar is painted with original Stihl paint, we'll tack on the stencil and paint with black and the bar will look brand new. I'll present it as a used bar, because it is, but this saw is so clean that a clean bar with new looking paint will definitely raise the price.
Time well spent for $30-$50 price increase? Maybe, maybe not. Depends.