https://www.lib.berkeley.edu/about/news/golden-gate-bridgeGolden Gate Bridge: Building a San Francisco icon, in photos
Has a photo of parts in question. The caption for the photo:
"The collection includes photographs from the Marin side. Steel for the bridge was manufactured by Bethlehem Steel at plants in New Jersey, Maryland, and Pennsylvania. It was transported by rail cars to Philadelphia, then shipped to San Francisco through the Panama Canal, according to the Golden Gate Bridge, Highway and Transportation District."