I'm not a big fan of roll pans, I like something hanging back there that at least gives an impression of stopping a parking spot dent. The original chrome bumpers were little more then decoration.
My trucks are work trucks, I build my own bumpers because I think the step bumpers are too wide for the step side trucks. I'll see if I can dig up some pictures of my old trucks rear bumpers.

The tan truck, though fenderless, has a standard width step side box. This one I built myself from 1/8" diamond plate. The blue truck got a step bumper with the ends trimmed back then reinstalled. It was probably 4" more narrow on both sides then a standard step bumper, once painted. I don't think it looked too bad.
The teal green truck has a stock 50s rear bumper, they were much thicker then the modern stuff. These are very hard to find. Not many trucks in the 50s got rear bumpers, and most that did didn't survive well. Gene