I had this reproduction Sunrad grille made a few years back, but no longer have a need for it.  The pattern matches the original grilles.  This one was never installed, it is straight with no bends.

Please measure your opening to make sure this will fit.  The edges are bent for strength, but there is no attachment hardware included so you'll have to figure that out (I've used magnets in the past).

There is surface rust so it will need to be cleaned up before painting. 

It is 51" long x 4-1/4" wide