There is no way to know how many days apart these cars were actually built.

The date on the tags & broadcast sheets is actually the Scheduled Production Date, or SPD. It is the date that they hoped to build the car, not a 'build' date set in stone.

The original door stickers on the other hand were required to indicate the actual final build month & year. This is why the dates on the stickers do not always agree with the SPDs.

Lots of folks assume that the cars were built in VIN order, but it did not happen that way.