Hey, Janey! Jaaaaannneeeeeeyyyyy! I found a box of attachments from long ago. Hoping I got them from the thrift store without the machine. Also hoping I still have the lid to the box. It has thst single hole throat plate you mentioned above (174529) as well as 14 top hat cams (series 173 amd 174) and mystery items #21906 and 163455 which look very interesting. It also has 2 snap on feet, which is strand, as there's no ankle. Hmmm. Oh, and the plastic bobbin is smaller on one side than the other.
Trying for a picture.