Teardrops n Tiny Travel Trailers

On a aluminum skinned trailer with 3/4" plywood sides, do the trim molding screws screw into the edge of the plywood sides? I'm not to that step yet, but I am looking ahead.

Thanks

...on mine, the screw wouldda been right on the edge of the ply...so, I glued an additional section of 3/4ply to the wall, the thickness of the spars, between each spar to help catch the screw...I also predrilled all the screw holes and shot a dab of sealant into each one..............
madjack