All later Contax were chrome. Rotating it clockwise advanced and cocked the shutter. No slow speeds to start with, that was one of the improvements which were added. That is how you can identify the first version Contax. The 50mm focusing wheel was ideally located for your index finger.
Later lenses have a chrome face.
Notice the chrome latch which must be depressed to remove the inner bayoneted 50mm lenses. I lenses have black trim, later Contax II lenses are generally all chrome. Rather than following Leica with a screw mount interchangeable lens system, Zeiss used a curious double bayonet system. The helical for the 50's was built INTO the camera body. As bayonet mounts go, this one is rather time consuming.