Bill in Sacramento wrote:
Having had a few months to think about serials and observe, I'm more than ever convinced that all serial numbers on Breitling cases refer to the year that the cases were ordered from the case supplier, and not when a watch was finished and sent out for retail. The watches were issued in serial and it is easy to account for changes in hands, dials, bezels, etc. over time, but not all dated to the year the case was manufactured. I think this holds for all serials since 1944.
I think it is very wrong to refer to the table of yearly serial numbers we use as "official" or from the original Breitling company. It may be from original company documentation, but I don't know the source and particularly whether it a compilation of when cases were ordered or watches delivered. Do we know where it comes from?
I don't know where Jean Michel got his numbers from, all others on the web use that data I believe. Richter has the same numbers, though only for chronos, but again could be the same original source. I don't think that we can treat it as 'official' given the lack of factory documentation from pre 1978.