> There's one (maybe more) exception to this: On HP pocket calculators, the date code?IS?the year and week of manufacture.
I don't think that's true, at least not universally.
I have several HP35s with the date code 1143 and it appears many were made with this number - too many for a week's batch, I think.
ref : http://www.vintagecalculators.com/html/the_hp-35_calculator.html
