Ford should've given meshes on such a premium vehicle. or there are no Rats in USA?
Anyways, I got my XUV meshed at ASC only. They used some body sealer (white goop to paste meshes). I am unsure if 3m tape will hold it. As there is often moisture and water in that area. A small bead of window sealer sillicone will help too.
BTW tata offers factory grille on all vehicles ( I opened it to check and seal vents, was pleased). All my safaris had the meshes from factory. But I sealed it with foam/ neoprene to prevent any dust and smell entry.