The sides sure are different, but the cupola and platform are an exact match. When you look at the second link for RYPN, you will see a photo of the preserved remnant that shows this same kind of opening in the carbody. The car was also acquired when the owner was in Pennsylvania, a bit closer to NY state than New Jersey. I was not certain at first, myself, but now I can't imagine that this would not be the 558, as why would they make an exact but modified replica in the 1950s?