Key wind pocket watches like virtually all before were in use and popular up until the third quarter of the 19th century .. if you have one it is most likely before the 1870's ... most I saw were about 1850s. I had several and sold them to buy some other watches I liked.   Little by little I have sold off many of my pocket watches.. right now I have only 5 or so that are keepers for kids and grandkids .. mostly railroad or highly decorated Elgins and such.