I have zero inside info on your question, but my guess would be that the fashion shots were done with Nikon or Canon 35mm cameras with motor drives. You always see the gals swinging from side to side and the photographers are clicking away like crazy. Perhaps in later years the went to 645's with an assistant changing the inserts every so often. I think I have seen assistants changing the film in 35mm's by first disconnecting the camera from the strobes and handing a newly loaded camera to the photographer. Speed was and still is very important I suppose when you are paying a model by the hour.