I also thought that they would be built in large batches (maybe 10-20 at a time, running down the assy line all together). From the dates so far, it's suggesting probably not...
There is an apocryphal story, that was probably made up, about what happened when Peugeot was asked why they did not change the wipers over on the 504 for the Australian market.
The alleged reply was because they make the entire year´s allocation before morning tea on one shift.
I call BS, because not only does that not allow for the UK market, but they would be having croissant, coffee, and a cigarette, not tea.