A mistake that made me very happy. :-) :-) :-)

[grsbanks]

HP weren't always 100% diligent in changing the serial number prefix every week and would often only do so either when there was a design change or when they ran out of numbers to the right of the country code.

Case in point, there's a metric buttload of HP35 units in the wild with a serial number that starts with "1143A"