Traditionally watch cases were made specifically for an individual watch and although there was some standardisation in diameter (The Lancashire size later taken up my the Americans and Swiss sizes in Ligne) the winding and setting mechanisms were not standardised and nor were features such as locating pins.
With the American drive to standardisation the "standard" watch case started to became ubiquitous during the 1890's with either a captive winding stem or a standard location for the pendant to support the winding stem.
This was a great help to volume case makers and supported the growth in plated cases as when worn out or damaged they could be replace off the shelf rather than having a specialist make or repair the old one at considerable expense.
It also led to a revolution in how watches could be sold at the wholesale and retail level. Watch movements could be exported and cased locally, often saving import duties, and more importantly watches could be cased at the point of sale.
So for instance an English retail jeweller in 1910 could buy in a range of watch movements from several makers, perhaps a selection by Waltham in different grades, some from Williamson or The Lancashire Watch Company and perhaps a few from Switzerland -where they had been forced to conform to the "Lanchashire" sizing.
The watch could be assembled by someone using a few very basic tools and with minimal training, in some cases this would be done "on-demand" at other times to pre-set configurations as stock moved.
A tiny number of these new and unused cases remain and this orphaned movement by Tavannes for J.W. Benson has now found a home in one such New Old Stock (NOS) rolled gold "STAR" grade case by Dennison.