Hello intraveno, I’m going to go at this from a different angle than the others unless I missed something already stated. No experience with Dodge Cummins (I have a 2002 F350 Power Stroke 7.3L. What I would recommend (from experience) is looking at the bed support channels- Ford are notorious for rotting, not sure on the Dodges. I removed my bed and replaced the channels myself- no big deal as I have the shop and tools to do it.
The other thing, personally I wouldn’t trust the 5th wheel rails bolts. When I removed the old bolts (twisted off with breaker bar and 5’ cheater pipe because they were seized up) I found that the bolts were wore 1/3 of the way through where they went through the ‘L’ brackets attached to the frame. Just saying- something to check in case you do decide to pull a 5ver later on down the road. My truck was 17 years old, yours has a few more years on it- but I like the older trucks...... best of luck.