Originally Posted by John E
My single data point, for what it's worth:
In March 1971, I bought a brand-new American Eagle Semi-Pro [Nishiki Competition], #KS78091. Sorry, I don't recall the serial numbers of the various Nishikis we sold at Bikecology, although I think many of them did begin with the same two-letter sequence as mine.
Funny you should mention Bikecology. I bought a Nishiki off eBay that was supposed to be delivered today. When it came up missing I tracked it to Bikecology in Terrance, Ca. Seems the seller got the box from them and forgot to peel off the old shipping labels. Doh!