[Daves55Sedan]

When I installed the rubber seals on my fender aprons, I used the original staple holes in the metal. Here's how. Begin by laying the end of the rubber at the end of the metal flange. Don't worry about cutting the rubber yet. Get a small drill bit that will just barely poke thru the staple holes. Hold the rubber on the metal flange and drill thru the holes from underneath. Now install the first staple thru the holes. Use needle-nosed pliers to bend the staples over underneath. No go to the next set of staple holes and repeat. Keep going till all the staples are in. Do them in order. Make sure there is no slack in the rubber before drilling holes.
You can also attach that separate lower splash panel and continue stapling the rubber onto it's flange so you don't have a cut in that piece till you get to the very bottom of the lower splash shield.