"Were Serial numbers added when the gun was ordered, and the ribs added just before the gun was sold? Or was it all a package?"
Argo, given that these gunmakers were likely to have several guns in build at any one time, logic would dictate that each already had a serial number allocated, if for no other reason than to keep all the parts for each particular gun as one 'package' as it went through the workshop.
I doubt that ribs were added just before the gun was sold, since barrels were made up and near complete prior to finishing. So the barrels were sent, perhaps in small batches of two or three, to the engraver for the name and address to be put on each rib. This would assume the action and other ironwork was engraved separately; perhaps some guns were engraved once complete and still in the white.
Some Beesley guns were built up pre WW I and not sold until the 1930s. Others were built and sold within several months, more particularly in the late 1800s.
Tim
