I've visited some years a go the JSB factory at Bohumin.
I made a big report of this visit but it's in Spanish. If someone is interested on it, please e-mail to me and I'll send you the full report
During this visit I asked to Pavel Kolebac the serial number meaning .
His answer was:
- The first one means the press machine used to produce it
- The two next digits are thecontroller operator identification
- The next two digits are the selection or sorting operator identification
- The last one is the year of production
- Sometimes appear S1 on the left side of the serial . It means a batch change, for example after the die subtitution to be repaired
Anyway I see the serial Nr you have has two more digits. perhaps the criteria has changed since the date I was there.
I hope this could help to everybody.