The carpet kit includes pieces to glue into the doors. The original cars never had door panels that I know of.
It's not uncommon that you'll see bare tunnels, trunks, ect. and only have the floor pan carpet. Some folks don't put anything in.
There are aftermarket door panels available, but you need to make sure they're for original cobras as some of the replicas have different sized doors.
http://www.kirkhammotorsports.com/ma...t/carpet.shtml