No.  The LED works only with an internal bluetooth card - the external one should have its own LED and can't be connected to the internal one.  
I have an Inspiron 6000 laptop.  It does NOT have internal BT  but obviously has the indicator light.  I just purchased a USB bluetooth adapter and it works fine, but the BT indicator does not come on or off when I enable it.  Is there a driver or fix I can use to enable the indicator for an external BT adapter?
Dell Inspiron 6000 bluetooth indicator