You might first check with either your rig's manufacturer or the manufacturer of your current steps to find out if there is anything connected with them that you need to know.
I need to replace the smaller set of Hickory Springs steps on our Jayco and have learned that, while the steps themselves are standard, Jayco uses several different methods of attaching them to their different models. HS has asked me to send Jayco my VIN so they can advise me as to what is needed, and only then can they, HS, advise as to just what I need to purchase. This should make life easier than if I had just ordered the best price set of HS 24"W and 9" riser triple steps and found installation was going to be a major problem.
'02 7.3 Powerstroke F350 DRW, Ford AIS
6.0 Cooler, PacBrake, Flashpaq tuner
2011 Eagle 320RLDS/Equalizer WD Hitch