'51 tail light question

[84RabbitGTI]

I have two styles of '51 tail lights in my collection.  The one on the right is from my 1951 Kaiser, the one on the left is from my pile of junk.  Note the metal insert in the center.  Is the right one an early example and the one on the left a later example?  Just curious.

[joefrazer]

It's the other way around. The one with the metal backer is the earlier style and once the bean counters got involved, they figured out a way to trim a fraction of a cent off the lens cost by eliminating the backing plate.

[84RabbitGTI]

Makes more sense, thanks.