Jim,
I would have bet the farm that stuff was heavier than that. It looks like it weighs a ton. Just a thought on the paint, if you beat them up too bad where they need repainting you should consider painting them with that black Duplicolor spray on bedliner paint that PhilD used to paint his U steps. I like the texture.
http://elcova.com/groupee/forums?a=tpc&s=2826088551&f=6706011751&m=133106684 &r=813105194#813105194
That would probably look awesome.