I can remember that J.C. Whitney out of Chicago had fenders in one of their earlier catalogues. Used to lump the group as 1960 to 1963. The first two years of fenders are quite different than for the last two years of the series. However, they used to mention that they were lighter and free from rust, which perhaps was their selling point.
If you come upon a set of these be sure they fit before purchasing. Compare your old one first. I do remember they were a bit thicker, and did not have things like the rubber hood bumpers, so your hood would fit unusual.
The 60-61 had more of a nose dive. If I put a 62-63 hood on my 60 it will look like the hood is not closed all the way down. Also quarter panels are different around the tail light area on earlier round bodies