Back when this gun was made, gun making centers like St. Etienne had plenty of outworkers. Only makers who produced a large number of guns could afford to keep all the workers they needed as full time employees. Small makers relied on outworkers and likely established working relationships with a number of them, depending on how many guns they were making. "The guild" process refers to someone learning the trade to start as an apprentice and eventually become an outworker in a particular specialty. The maker had to make sure that the gun was moving from one outworker to another, and would have been responsible for paying the outworkers.
Just as an example, I have a British 20ga Crudgington which was made far more recently (1966) as ordered by a customer in California. Along with the gun I received a copy of a letter from Mark Crudginton, the owner's son. The letter lists the names of half a dozen workers who were the actioner, barrel joiner, color case hardener, final finishing (the owner himself, I. M. Crudgington), and stocker, as well as a couple possibilities for who might have done the engraving. Smaller makers like Crudgington (they also own Gibbs and make more guns under that name than their own) still rely on outworkers.
I recall reading that one of the owners of the French maker Vouzelaud (are they still in business?) spent a lot of time on the road traveling to St. Etienne and keeping in touch with outworkers who were involved in making guns for them. So the system is still in place in some gun making centers in Europe, although the total output of doubles is much, much smaller than it was back when the French gun under discussion was made.
