Universal 1 ink drum core “keeper” missing

In cleaning up our new Universal 1 at OCAC, we discovered a missing piece that keeps the ink drum from having side to side play. It’s this “keeper”, or collar as I’ve been calling it, that fits around the ink drum core that sticks out on the outside of the non-operator side of the frame.
Does anyone know if this part has a part number? I do plan on putting in a call to NA Graphics, but I thought it might be helpful to have a reference.