Are we really quibbling about a couple of years, John? :24:
They're both Michael Harris period, I know the generality is that necks and flanges got longer and thinner and less buttony, but there's also the sort of thick cup-shaped one .... and it's only a generality.
I've got a bit of a suspicion that yellow alone is very early.... that once they got going with blues as well, they didn't really go back....
only a suspicion, mind, no proof, no evidence, nothing.... other than a distinct shortage of them.....