Those look like they would work with many machines, besides Singer. My 237 has a shuttle body and bobbin case like that.
I can't remember, off the top of my head, what the difference is between the bobbin cases are.
(Not affiliated with links )
https://shop.sew-classic.com/Bobbin-...ger-JO1313.htm and
https://shop.sew-classic.com/Bobbin-...-JO1313Z-J.htm
Janey - Neat people never make the exciting discoveries I do.