I managed to break the front windshield washer fluid bottle/reservoir for my 1987 W124 300TD wagon yesterday (cue applause!). I have posted a request in the parts wanted forum, but I had a specific question about something in EPC. The original part number was 1248690120 which was changed at some point to 1248690620. But for that current part number there is a note which I don't understand:

Design Change - On model 124 133 Part Number 1248690620 Is No Longer Available. Part is Subbed In System to 1248690920 and Requires FN 409. GR86/030*.

Does anyone know what FN 409 is and whether 1248690920 would work in my car? Please note that my model is a 124 193 wagon (not the 124 133 sedan mentioned in the note). How can a part be unavailable for only the sedan, but still supposedly available for my wagon?

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).