Chevelle grill is the one stamped in aluminum. Just like Indian said: - Beaumont grill is all cast...white metal just like V8 emblems, door handles & their head light bezels
To actually redo a pot metal grille with chrome, is a time consuming process, to do it right. First stop is chrome shop, chrome before paint, then any areas that need paint, chrome needs to be scuffed with fine grain paper, paint doesn't stick to chrome very well, any rock chips, nicks and pits are filed out with flat files then filled with bondo, sand primer, paint, install. I've spent over 150 hours on just one side of a grille filing filling and sanding.
If your grille is rechromed you shouldn't have any nicks/pits... but rechroming a Beaumont grille will not be a cheap project, especially at a show quality chrome shop. If you do explain what you plan on painting over after, it could bring the price down, as they won't prep those areas the same.