I put a double step on mine, and like has been said there is adjustments that have to be made. The new step was a little wider, not a big problem just drill another hole. The biggest problem was the depth of the new one it wouldn't span to my next i beam. So i had to buy 2 pieces of flat steel to span the distance, and then bolt the new steps to the flat steel.
2013 Rockwood popup 2318 g. TV 2003 trailblazer and a 2013 SLE Sierra p/u