Allen makes a good point. May be best just to let the steps be a little scuffed. May not be all that noticeable under water anyway. Vinyl ester resin is probably on the top coat of the fiberglass but why guess and then potentially have a problem again? Worst case is you get some bubbling of the fiberglass before the season ends. If this happens and becomes a problem you can deal with it then or just leave it. Most likely won't if it behaves like a boat bottom. This process normally takes a year or more.