A few more details: The Chrysler 300 grille was marked as a '62 on the package, but it's really a '61 due to the "CHRYSLER" lettering on the top - that was '61-only. Good to know if you want to convert a Jo-Han '61 New Yorker to a 300 - although I recall it being a little larger than the Jo-Han grille.
The '57 Buick grille is different from the one in the old '57 Chevy kit; the parts pack one is wider and more curved - possibly Super/Roadmaster.
The '60 Mercury grille has separate inner headlights like the custom piece in the '59 El Camino kit, but the lenses are molded in. (Anyone have both on hand to compare length?)