If I understand correctly stairs have little (or nothing) to do with grade. They are either full stairs (FS) or not. Sort of like a grade being affected by whether a 1955 cent is a DDO or not. It doesn't matter.
The surfaces are very clean but I'm concerned that the coin just doesn't have the luster necessary for an MS66 grade. I'm going to say MS65 on this one. A nice album coin IMO. As noted, the steps is a designation and is independent from the numerical grade.