They are the same electrically. Whether there is any difference in the minutia of how the primary and secondary couple high frequency noise on the mains I wouldn't like to say. There may or may not be any difference there and if there was it would likely be a half of a quarter of nothing.
I would normally connect 6 and 7 together as in the top diagram, since they are adjacent on the terminal row.
But probably better still to connect those windings in parallel and feed them into a bridge rectifier. In the circuits you show each winding only supplies current on alternate half-cycles, so in each half-cycle twice the current is flowing for the same output current. This increases heating in the transformer windings due to (I^2)*R.
Not necessarily a problem if the transformer is lightly loaded though.
Not necessarily a problem if the transformer is lightly loaded though.