Just picked this beauty up off evilbay, I believe it is a 595/1 camera.It takes 122 film and its in great shape. It came with a combination back and a number of sheet/plate holders, ground glass insert and a pack film holder.The plate holders are numbered 721/6,the film pack holder is numbered 723/6 and the ground glass insert is either 639/1 or G39/1. There was included with one of the plate holders a film sheath which measures 3 7/16" wide by 4 9/16" long and has a semi-circular cutout in the top right corner. Is this the right sheath for these holders?.

Any help would be appreciated