I just read this post.
Our Jukebox-World database does not list lowest and highest production number (yet).
It lists those numbers user posted already. This means it is not complete yet.
The heading of the table says "Serial number entered so far".
Tom did collect numbers for many years and it must have ben quite time consuming for him.
For model 443 he could get 13 numbers and gave the number range 420,867 to 428,939.
We collected 27 numbers until today. So far the known number range is 420,000 - 428,584.
This means at least that 420867 is neither the lowest 443 serial number nor 428584 the highest one.
The same we figured out with some other models. On some models we could collect lower or higher serial numbers than Tom.
The conclusion to me: No database is only right or wrong but combining both can give a good idea about lowest and highest number.
Especially since we can't ask most manufacturers anylonger - and if so they probably would not tell.

Only NSM gave us a list about the production amount - but not the serial numbers belonging to it.
Everybody is welcome to enter serial numbers which aren't entered yet! The database is kept in English.
http://www.jbw-forum.de/sdb/Kind regards - Hildegard