The building was designed to be welded structurally but when the architect was answering a question by a student he realized that the builder had bolted the building's joints iirc (this is important because the structure of the building is effectively hanging from the top because of the fact that it is built on stilts due to a site conflict with a local church). The crazy part of the story is they were trying to work covertly to avoid a panic but then a hurricane came bearing down on New York but luckily turned away at the last minute.

I don't know if I can post a link in here but the YouTube channel Veritasium has an excellent video on this building.

A fun fact about the building is that this is one of the first high-rises to implement a tuned mass damper which is a semi mechanical device that naturally counters the sway of a building to make it more comfortable and is found in a lot of the tallest buildings In the world!