David, I was standing when I took that photo. I'm 5'10" tall and was looking up. I haven't been able to find any evidence that the bridge was gated at one time, but I also can't prove that it wasn't.
As to the unknown fixture on the pier.... It's hard to see from the angle of the picture how high it is above the deck.... if it's not too high, I ahve a strong suspicion that it is a hitching post. Let's remember when the bridge was built, there would have been only horses....this is my best guess.