Swapped out my suede knee bolsters for leather. Used a "Premiere Dual Tip Design Marker by Nicole" to match the orange stitching, color is Tangerine. Color appears to be a perfect match. I saw a post somewhere on the web about using a fifty-fifty solution of vinegar and water to dampen (not saturate) the threads and then carefully go over them with the marker so that's what I did, time will tell if it lasts. Hopefully the vinegar and water solution didn't do anything to the leather.
The armrest on the bottom is an original Fifty armrest, used it as a comparison to see how the color matches.