Those roll-film backs that slide in under the ground glass like a film holder were not a Graflex product. Calumet has been the major manufacturer of those, but there were other vendors along the way. It is possible that there was one for the smaller than 4x5 view cameras, but you will just have to search the auction sites, etc.
AFAIK, all the Graflex (brand) roll-film holders were designed to replace the ground glass back and required a Graflok back.