For those that use the BeagleBone flasher images there was a recent change posted. For new images, the four LEDs will be OFF when the flashing is complete. Previously, they were all on.
The change will improve the reliability of the micro SD card you use to flash the Beagle as the board will now be shutdown by the flasher script. Most of the blogs and instructions out there will say wait for all four LEDs to be illuminated when done. However, the reference instructions has always been at the eLinux Beagle Board Debian site.
The latest images are available from BeagleBoard.org. When you flash your new Rev C, keep in mind this change!