5K has four buttons and two LEDs. The volume buttons are with Red LED, and multi-functional buttons are with Blue LED. You can easily recognize and distinguish the left and the right buttons by check the LED color.
Volume Buttons & Red LED
Multi-Functional Buttons & Blue LED
One of the Blue buttons has a small bump on it. It would help you to distinguish the buttons.
*Please note that the LED intensity is not uniform around the entire button area, and may not be bright enough at daylight.