LED Notification is indeed being controlled with codes BUT the only thing that will allow you to have different LED light colors just not rely on the codes only since the HARDWARE needs to be compatible with the codes as well.
Our AF2 ONLY have a white LED bulb. For different colors to work for specific type of notifications, the bulb needs to be an RGB bulb. So the restriction falls on the hardware-part in this case and not on the codes.
If you want to try it out, you can try an app like https://play.google.com/store/apps/details?id=com.koo.lightmanager (does not require ROOT) and you can go to the Test section at the lower part, you can try to set it to a different color and select ENABLE.
I've used that app before on a different android phone and as long as the phone have an RGB bulb, it works fine.