Balun Polarity Importance
Two things you should know. Mouser and other suppliers have listed it as a discontinued part. That means you can buy it cheap while stock last. The second thing is that your second drawing is correct, the way you say it is wired on the PCB. Think about it. For a balanced output you need both a (+) phase (no dot) and a (-) phase (with a dot). The first drawing will NOT work because there is no difference in the output wires-no signal. Also the Iw marking is wrong in the top drawing as both currents are flowing in the same direction. Your instincts were correct. The PCB is wired as per drawing 2.