I added a page for the Colt R6430 9mm Carbine with ‘CS’ stock. An example recently auctioned on Gun Broker and was a great deal for the buyer. You can see details here: https://thecoltar15resource.com/r6430-9mm-carbine/
The Colt AR-15 Resource
"A site dedicated to the history of the Colt AR-15 rifles, carbines and associated items"
The Colt AR-15 Resource 