Dark Fawn is used only on the top of the dash - between the windshield and the dash pad. I chose to paint mine all the same color - personal preference / not have to buy additional paint.
Concerning the match in color, we painted the section right under the rear glass with the sunlit sand but the section where the gas tank once sat is still original GM silver fawn poly and other than the gloss there is no discernible difference in color that my untrained eye can see.