I don't see any reason why you couldn't bolt them into a Cummins truck assuming it's the same generation. I would check and make sure the stroke length would work, mainly that you didn't bottom out the shock during compression. Other than that drive it and see how it feels. In the end you are talking about the cost of a used set of shocks that you can swap out in 30 minutes versus paying $1,000 for springs, shocks, and a track bar........
I understand the thought process that the shocks must be different because the coil spring rates are different because of the increased weight of the Cummins, but we are not talking about desert race trucks or Ultra 4 cars that are fine tuned. If you go to most parts website they list the exact same shock whether it's a Cummins or 6.4 powered truck. Thuren doesn't even give you an option between what engine is in the truck when ordering shocks (coil springs yes, shocks no). PW's do have different part numbers at most places but that is probably only because of the length differences, though for normal driving I doubt you would ever get into issues with the stroke.