SMC inner apron is held on by SMC bonding adhesive. Heat it with a heat gun and it will come off. Scribe into the paint around the edge before removing. So you can line up the new one. Put the new one in place temporaraly and fit the fender and hood. If everything lines up, drill a few holes to referance the position and cleco on. Remove the liner, sand the area for bonding adhesive, apply it, then reposition the inner liner and cleco & clamp it down until it's dry.