Slide out topper install question

 I recently purchased two slide out toppers (Dometic Elite Slide Toppers) for my 2018 Colman Lantern 314BH camper.  My question/concern is:  Will I have any issues installing this on a camper with ribbed aluminum siding?  All the install tutorial videos I’ve watched are on campers with smooth fiberglass siding.  With my ribbed siding, something might not lay flat on the side to screw in a piece. 

I’ve called camping world and Keystone and they keep referring me to other people going around in circles.