Wire harnesses. When did the design change?

There's been a lot of "little" changes year to year. Even in the early ones, one or two years had the "safe" bulkhead connector for the ammeter and I thing they were separated by one "unsafe" year. Some years the shape of the connectors are different. Without laying the two harness out side by side, untaping them, and doing a wire x wire comparison with a service manual, I have no idea. 71; 2/3/4 5/6 were all some differences.