I got an aftermarket stock that came with the pad installed. The shape and fitting to wood are fine but it's got some fairly coarse sanding marks left in the rubber (elsto-polymer, whatever). My question is what grit paper and/or technique should I use to get a nice smooth final finish?

Thanks. -WSJ

If the fit is fine, you don't want to do much more than lightly hit the surface with anything coarser that 120 and keep it wet so it doesn't clog up. The company recommends WD-40.