In my ongoing search for Colt AR-15 accessory items that were sold individually, I found a Colt Sporter Cheekpiece that was sold on Gunbroker.com. It was basically new in the box. Unfortunately, I was not able to buy it.

I have added images and a little bit of additional information here: https://thecoltar15resource.com/colt-sporter-cheekpiece-pn-ca10026/