Remember the Singer Co. is a different company now. They have merged with Viking and Pfaff. So they are changing things. When buyouts happen info is lost. We owned a business and used serial numbers and model numbers for our business and it became hard to get parts for certain items because of mergers. Surely some other source for the info is available. Contact
[email protected]. They have a business for replacement parts for the Featherweights and I am sure he has correct info that you may need.