(Don't have car yet.) It seems that no center caps are included with the hubcaps. Would adding center caps do any good, as far as cleanliness, etc? Toyota doesn't include them, so apparently it doesn't think so.
It certainly does include them, on any models without full plastic wheel covers. That’d be any 5th gen with 19” wheels if I’m not mistaken. New York State has more than its share of road salt; trust me: that’s one good reason for them. Carefully applied, regularly revisited rust-proofing is a good ploy in the salt belt:
