You are pretty much right Kent.
I made one very simple error in assuming that all serial numbers issued were unique; they were not.
I dug a little deeper and found this serial number supplied on No 1B Quick Acting Ordinary Portrait Lens supplied by Dallmeyer in January 1865.
See page headed 234 in the link below

This is an excellent resource for anyone interested in the old lens types.
The home page is at:

and is well worth a look.