I agree the scrapes through the finish at the mans foot look suspiciously aluminum with that whiteish color but the screws are period correct versus Phillips head screws used in many modern reproductions.Dunno..
They're made out of aluminum, I've seen a few. They are just modern (now vintage) replica types made in the 60's and 70's.
Collectors of American antiques love weathervanes. In fact, people love them so much that during the 60s and 70s antique weathervanes started disappearing from roofs across America. Thieves were stealing the valuable vanes in the middle of the night. I heard stories of weathervanes being stolen away by helicopter – they swooped down and lifted weathervanes off of barn roofs.Antique Weathervanes | Original Surface on Horse, Rooster, and Car Weathervanes | Skinner Inc.