This is the wiper seal that is used on our Montana, and on the Trekwood site, it shows that it is also used on your rig. Sold by the foot, order the length so you have at least as much as you need to the full foot length. The seal has a screw at each end through the rubber into the flange it clips to. I have replaced all of ours and it's not hard. Use a side cutter to cut through the wire coil molded in, and a utility knife to cut through the flap part.
https://www.trekwood.com/products/19...lip-On-1225-Bx