I have a question about installing a bath tub wall surround. How well will the adhesive hold on the old board

I had to remove a large portion of the existing greenboard due to water getting behind the wall. The studs were moving, which broke any seal along the tub, so I needed to take out a large enough section of the board to reinforce the studs. the remaining board on both sides is in great shape, and replacing it would entail more than I want to get into at this time. The problem is, when I took down the tile, the paper tore away from the board in some spots. I was going to skim coat the entire surface to bring it flush and smooth out any imperfections. My question is, how well will the tub surround adhesive hold to a surface that was skim coated with plaster or joint compound, or will the remaining board surface be ok to hold the adhesive?