I do not know if there is a "standard" pin numbering for this connector; in an attempt to avoid confusion if there is, I identify the pins here with letters rather than numbers. This is a view of the connector on the board, held with the pins pointing out of the board towards you. This diagram identifies what the pins are connected to on the mating connector; in particular, I don't know whether pins A and F are actually connected to something on the board.

            _____
           |     |
        +--+     +--+
        | A   B   C |
        |           |
        | D   E   F |
        +-----------+