The script will insert the displacement maps and appropriate settings for each level of intensity.  It will not disturb any present image map already available for the model.  However, do keep in mind, any displacement/bump you use is dependent on your Poser unit of measurement.  If you are using a measure of feet in Poser, setting a displacement value of 0.1 translates to 0.1 feet.  You will not see any significant displacement.  Now change your unit of measure to inches in Poser, 0.1 inches will show some displacement in the render.