Those louvres are directional, meanig theres a left side AND a right side. I know of NO current model kits that are like that! The fact that it'sa wagon, and those louvres are unique makes finding them LIKE that are very slim. MAYBE you can,as was suggested, scribe them into the fender tops with a scribe. Lay a tape line at the top and bottom. and with a pencil, draw the lines in, then try to scribe on the pencil lines. It will take a pretty steady hand, but with some patience, and time, you should be able to do it.