Over the years there were a few alterations to the Featerweight. RebeccaG, have you looked up the serial number on yours and found a production date? Among them were slight changes to the the bobbin case, race and hook, if you ever need an extra for some reason (like having one dedicated to a particular thread weight) make sure it's the right one.
Here's a direct link to a manual. I like the chromed plates with the art nouveau decor on the chromed plates, I hope a 201K2 will turn up near me one day :- )
All this information can befound various places on the web. There are lots of blog posts and even a facebook page dedicated to this model.