I did a whole thread on them. I like them and they have kept a ton of junk out of the underneath of my truck. The trickiest part is at the front of the wheel well, where they kind of go around the little trim piece. If you got on the ground and looked at that spot real close you'd deduce these are aftermarket - the fit is OK but not "factory" - but you can't see it unless you were down there looking for it and knew what you were looking for. The rest of it you can't tell one way or the other if they're factory or not.
Let them sit in the sun for an hour or two before you get started. They're thick and not very flexible, and if you do it when it's cold like I did you will work harder at it. If you have rear mud flaps they have to come off and go back on. If I bought a different Ram, I'd buy these again.