Wire harnesses. When did the design change?

Those HD terminals between the the pair of plugs were used only 2 years 63 and 65. Why skip 64 and not use them ever again - who knows. Probably because the bean counters said it was cheaper to use terminals. Anyway, on the engine side the black wire go to the output of the alternator; the red ends up at the battery positive. On the inside they end up at the alternator