Below are 2 photos of AC line filter "LF2" from two different Macintosh 128k~Plus Analog Boards. The newest board is stamped 4192 (1986 PCB), which I assume means 42nd week of 1992, and uses the LF2 without the green Earth wire. The other PCB is a 1983-84 version stamped 0792, which I assume means 7th week of 1992, and you can see it has the green earth wire wound inside LF2. Indeed, most every Analog Board I've seen has the Earth wire wound in LF2.
Why do you think the green Earth ground wire was not wound into LF2 on the 4192 board?
By the way, the 3-pi