New renderings of One World Trade Center released last week give a more detailed look at a slimmed-down design for the Lower Manhattan Skyscraper’s 408-foot spire. Not only could the design change keep the tower from reaching a symbolic height, it might also compromise its bid to be the tallest building in the United States.

Skidmore Owings & Merrill (SOM) and structural consultant Schlaich Bergermann und Partner’s original design for the spire enclosed it in a tapering shield of white fiberglass plates. But last year, in a move that saves $20 million in construction costs, the development team of the Durst Organization and the Port Authority of New York & New Jersey decided to take off the cladding, resulting in the narrow metallic mast visible in the recent renderings. If that spire is just a bolted-on antenna, rather than an architectural element, it would not count toward the building’s official height, according to the Council on Tall Buildings and Urban Habitat, the organization recognized as the official score-keeper for towers across the globe.