My (new to me) PU bed is 49 inches. I explored every option I found on the Internet for my specific camper, and tried adapting bumpers n steps from any/all sources. All options were too short/wide/narrow/etc.
I finally gave up and ordered the 6 step scissor steps (Glow Steps), and when I received them, the instructions stated something to the effect of "Do not use on Northern Lite campers without a rear bumper".... Which is exactly what I was going to mount then on.
I mounted them anyway, but will support some of the weight from underneath so all that weight will not be swinging free during travel like my four step setup on my Alaskan Camper.
Both my wife and I are happy with them. They are MUCH sturdier than the 4 or 5 step other brands that I had experience with.
That doubling on the side supports really does make a huge difference!
I would heartily reccommend them.