One thing that has LONG been a problem for C126 coupes, has been the lower quality of the hood star, which leads to fading and eventually complete washout of the star's color, to the silver aluminum color.
Recent versions of this hood star have been PARTICULARLY bad, with fading of 50-80% happening in as little as six months. I had replaced my SEC's hood star with a new one just one year ago when I had the car repainted, and it is already around 60-70% faded with the color gone.
At $40 list price ($30 discounted), these stars do not come cheaply, leading one to take steps to try to preserve the color and condition initially upon acquisition.
I recently purchased a new hood star (proper MB part number is 107 880 00 88; DO NOT use the plastic hood star that is now superseded to the SECs, which is used with the R170 and other models, and DOES NOT fit the C126 hood holes correctly). I also purchased three of the small plastic grommets which the star uses on its long pin to fit into the SEC's bottom-most hood hole.
Before putting the hood star on the car, I applied six thin but cumulative coats of clear acrylic from a spray can (obtainable at any Home Depot or Lowe's) in an attempt to try to protect the hood star from fading and the weather. I let it dry for approximately one week on the work-bench, and then installed it onto the car today.
You can see photos attached of the star on my desk after the acrylic was dry, and installed on the car.
I will report back in a few months to see how things are wearing.