I believe it is the same as was used in later Kenmore machines, based on an old White rotary manual from ismacs.net.
I have owned several Kenmore 117 series machines, and the bobbin case looks to be the same as my newer White rotary, they take the same bobbins.
look on craigslist or FB marketplace for Kenmore 117 series or White rotary, find one cheap enough and make sure it has the bobbin case first, after checking Ebay, etsy's, and other possible online sources for just the case.