Playstation 3 Controller question...

I have two PS3 controllers a Japanese retail one and a Test one (for use with the PS3 prototype), the prototype when low on battery flashes a red LED inside the PS button and when charging the PS button glows red where as the PS3 retail controller does not.

Is my retail pad slightly faulty or does the prototype / test pad have an extra LED?

 

Proto pad has an extra LED. The PS button doesnt glow at all in a retail controller, though if I remember correctly, it does have a spot for a 5th led

 

They both have LEDs from what I know only the retail doesn't use it. So it's not faulty