Those that Dan posted, look very much like the ones that Miller Meteor used. As for finding used one, it might not be that easy. I have quite a number of rods that I purchased over the years, and what I realized is that there are no 2 cars alike when it comes to the rods. They drilled the holes, and made a rod to fit that door. The rod from the left side of the car is different than the rod from the right side of the car, because they were all "custom" built. I got curtain rods out of a 1962 Olds CB, which is the same body as my 1962 Chevy CB, and not one rod is the same length, as what was in my car, nor are there 2 alike from the Olds.
Every rod that I have seen from that era was steel, and then chrome plated.