When I bought my 1910 colonial the entire house including the staircase was carpeted. The original baluster leading from the second to first floor had been removed and replaced with vertical brass bars. Upon removing the carpet I found and restored the original tread and risers. However I have a slight issue. When the stairs were carpeted they also added blueboard over the original horsehair and plaster (which had been paneled as well) and cut off the over hang of the sides of the treads of the stairwell (there is exterior wall on the other side of the tread). Each tread has an overhang over the riser. I could remove the front overhang and replace it and add one to the side in order to finish it but I'm trying to avoid that as much as possible.

Was thinking of a skirt on both sides (exterior wall and blueboard right side of stairs) and then a 90 degree piece of molding but with the front overhang I would need an inside filler on each riser.

Any thoughts?