If all you're missing is the hook, I'd probably fix it. If the bobbin case is the wrong one (the 11 oclock should fit a 15-90 or a 15-91) then the one you got with the 301 should fit it. It's a SS only machine.... Unless I'm wrong, all you're missing then is the hook... I'll PM you when I figure out which one it is. I'm really slow this week though, the roof is taking way more time than I'd anticipated.