Confirmed today that the OE running board mounting points are exactly the same design and spaced exactly the same between 4th and 5th Gens.
I installed Go Rhino 67427T oval side steps from a 5th Gen onto a 4th Gen (technically a 120 series GX470, but same difference). They fit perfectly. The steps sit fairly high on my truck, but I think these particular steps are designed to be that way even on the 5th gen.