It should be noted that practically all mechanical clocks that have been made within the past 100 years, i.e.
those that are not antique, have been made in a factory using mass production techniques.
However, if you don’t there are various little things that can help when dating antique clocks.
One of the many makers of these sorts of clocks, as well as other styles, was Frederick Japy, whose Japy Freres would become the leading French clockmaker in the 19th century.
From the 18th century onward, longcase clocks were made in Normandy at Saint-Nicholas-d'Aliermont, near Dieppe.
During the Regency period (from roughly 1715 to 1723), bracket clocks, which had been popular a century before, came back into prominence.
A bracket clock could be hung on a wall or placed on a table, making it a flexible timepiece compared to, say, the longcase clocks that were also being produced at that time.