Rollfilm backs for Graflex 2x3 are dedicated in size for the camera. (i.e. 4x5 backs won't work.) I have a Graphic 23 RH10, which is a 6x7 back for 2x3 cameras. I believe these backs are Graflok, but I attached mine to my springback camera with a set of springs and screws.
I can't answer about it fitting on a Busch Pressman.