The front nozzle may have been so worn where it slides down over the cross bar, that it would go on and off because it would not engage the safety switch properly. Hence the front nozzle with the red trim. The bojack paper bag conversion was an option for someone that did not like the dust associated with the old pocket bags. Fairly common stuff back in the 80's when you would see quite a few of these come in for repair. They were more concerned with the function, not with the potential value of it's originality 30 years later.