I think you missed the part about the gas tank changes shape in 1981, it is noted from the post I reposed (orig post of this thread), unless you was referring to the image above. I don't think the list includes all changes, because it would be pages long for any major redesign, I think the source was a physical book, so there was limited space to publish the changes, it was just an identification manual to help identify models.
1980 - A First Gen
Only new decal design. New engine number configuration starting with TB02E~, new model ID system, this model "A"
1981 - B Second Gen
Fuel tank changes shape, Introduction of the much welcome "CDI Ignition". Headlight changes from round to rectangular. Electrical system switches from 6v to 12v.