I reached out to my contact in Vienna and got clarification. He is the product manager for the K702-65.
[size=11pt]"Concerning the serial numbers:[/size]
[size=11pt]Usually we do not start at zero. Depending on the product, numbers below 100, 500 or 1,000 are reserved for internal use. They are reserved for our internal pre-production test series and trial series in order to test the products, assemblies, parts, color, material finish, vibration tests, acoustic measurements, and so on. Moreover, sometimes we skip a range of numbers for customized versions. Therefore, it’s hard to tell which number will be on the last headphone leaving our factory. [/size][size=11pt]It might also happen that our QC department banishes some numbers in case they did not meet our strict requirements".[/size]
I hope this information will ease the minds of K702-65 owners and clear up any confusion around the serial numbers.
~ Mike