I have for sale a vintage custom license plate frame and mounting panel. As you will note in the pictures it has ribs across the top and on the sides. The frame appears to be die cast. This was a moderately fancy accessory back in the good old days. I am guessing it was manufactured in the '60s or possibly even the '50s. As you can see, the tin plate mount needs some attention and The chrome has some bumps on it, but I think it shined up quite well. It is not perfect, but I have not seen another one quite like it.
$29