May be I can help.
Isn't the K-line just for diagnostic purposes?
But the radio gets all of the following commands by CAN bus;
Ignition for ON/OFF
Illumination
Speedometer signal for speed dependet volume control
Steering wheel controls
Display in instrument cluster.
Did I forget something?

Not having code numbers on those radios would make sense, if you consider that the ones mentioned all have odd shapes and can not easely be installed in another vehicle, and therefore don't realy have a resale value.