I would think you would be fine, dash pads are pretty stiff when removed from the dash and in my experience fit right back on without tweaking. Follow the instructions that come with the dash cap, silicone around the outside edges only, not the entire surface of the dash pad. lightly sand the areas you will be putting the silicone on, cut out any raised areas of the dash pad and allow an overnight dry time for the silicone...
to see how much your dash pad will flex when reinstalled... lay it back on the dash in the correct position, hold down one side of the pad lightly but firm. Now push down on the other side and see how much it "teeter-totters" If it doesn't have much play or slop, there shouldn't be a problem... if it "teeter-totters" and lots of play... you may not want to risk it.