f300 Serial Numbers

Many years ago, my grandfather gave me an early Seamaster f300, which I have treasured. Recently, I acquired another f300 Seamaster from him, this one a Cone. Both are in less than perfect shape, and both have gone back to Omega for repairs. Omega has provided me with their serial numbers, which has given me a moment of pause.
Both watches have 32xxxxxx serial numbers, which seem to correspond to 1970, but it seems that the f300s were first produced in 1971 or 72.
Thus, I'm curious as to which bit of my information is wrong - were f300s produced earlier than 72, or have I got the wrong idea about serial numbers?

Here's my earlier f300 - gold plated on black leather



Versus the recent acquisition - a very battered Cone with a blue face and glass scratched to all blazes, with corrosion on the dial and a slew of other issues listed in the Omega service report. Given that my grandfather wore it every day for the best part of a decade, and took it sailing frequently (it featured in his infamous triple-roll of his little catamaran), I'm not surprised that it's so beaten up.

Any advice is much appreciated 😀

Thanks, that's some great info, as well as an exquisite watch. 1970 would fit, and Grandad used to always talk about them having been examples of Omega's newest watches when he got them.
Part of me is tempted to get an extract from the archives, but I don't know how expensive that will be, and these watches are already costing me a pretty penny to bring back to life

An extract will cost you 120 USD. Nice Watch btw.👍

Ah, that was me being blind 😜 I did some poking around on that site, but somehow missed the section on serial numbers. Many thanks for the link 😀