If you are referring to the green circle as #1 in your schematic, thats doesn't look like the part. That would be the one that is right behind the rotor cover. Would it be whatever is connected to #25 bushing that you are looking for? TBH, I can't even find that piece in the parts catalog either.
PG 3C-12 and 3C?19 in the Workshop Manual
No part number anywhere. Is it welded to the frame? Or is it bolted? Hard to tell from your pictures.