There were very early first-generation 6-speed freehubs that held the freehub body to the hub shell with splines and just the axle and cones to retain it. They did not use the current hollow bolt. However, I don't know the model number(s).
I came across one of these on a '83 Trek I bought used. The previous owner had upgraded the original freewheel hub to one of these early freehubs and I discovered it when I went to overhaul the bike.