So, as I remember about 8000 k0 have been produced. The first 1500 were fitted with a wrinkle tank... well that I have been reading somewhere.
The wrinkle in the tank was not intended but due to the fact that the pressing of the lower steel tank sheet actualy went to fast. And therefore startet wrinkling.
Since there was so much demand Honda didn't fix this right away. Since you could only notice it with the tanklid open... who cares. When the press was adjusted the new tanks without wrinkles were immediatly used. But since there were still wrinkle tanks lying around and demands remained high newer bikes could still be fitted with wrinkle tanks thought for spareparts.
The more I learn about what should be 'original' the more I find out there are so many differences (small ones).
I guess no one at Honda said to the management (for example):
' Hey listen; we cannot ship this bike like this! The wrinkle tanks should not be fitted on frames with a serial number higher than (insert desired serial number here)!'