Looking at the Dodge instructions (second set listed for the p/n's) they are mounted by drilling through the pinch welds. I am not a fan of this type of mounting, but you may be, so it's your call. I prefer the frame/cab bolt mounting. There are several steps out there that are mounted thru the pinch welds and the guys report that they are strong mountings. Maybe someone here has them or can discuss the pinch weld mounting from their experiences. Years ago I mounted a set of steps on pinch welds on a GMC truck I had, lots of rust at the mounting points. It is next to impossible not to have rust over time due to/because of the back side/in between metal area that collects moisture.
CD