yes, you can make a Selection tag of the face polys you want to use then add a Restriction tag to the Displacer deformer and drag the selection tag into that.
you could also use displacement in a material by stacking the materials and limiting the material using displacement with a selection tag. This would render slower if you use Sub-poly displacement but you get to use sub-poly displacement, so much more detailed displacement and you don’t see the displacement until render.