340 K Member ??
So from what I have seen in this thread…. Starting sometime in 69, 340 k-frames (regardless of options) got this washer (probably as some form of identification) and the washer continued in use through 72 (not enough info on 73s).
Only 1 claimed to have one on a 68 (I don't trust that claim to be accurate).
Only 1 claimed to have one on a 318 car (I don't trust that claim to be accurate).