NEW YORK (CBSNewYork) - It turns out that One World Trade Center, which just last Monday took the title of New York City’s tallest building, might not become America’s tallest building.

WCBS 880′s Marla Diamond On The Story

The Port Authority and the Durst Organization have changed the tower’s design, according to a report. Chief Architect David Childs told the New York Times the co-developers decided to remove a decorative shell from the antenna mast that will top the tower. That change will likely bring the height down from 1,776 feet to 1,368 feet.

SEE: Latest Photos Of One World Trade Center

Without the 408 feet of spire, One World Trade Center would not be taller than the Willis Tower in Chicago, which is the tallest building in the United States, standing 110 stories and 1,450-feet-tall.

“We count spires toward the height, if it’s part of the architecture, it it’s part of the actual design of the building, we count it toward the height,” Kevin Brass, spokesperson for the Council on Tall Buildings and Urban Habitat, told WCBS 880. “But antennas, or any other apparatus that are simply put on top of a building, we do not count toward the height.”

The Council is waiting until the building is complete to make its final decision, but things don’t seem to be leaning toward the antenna being counted without the decorative shell.

“This definitely raises questions,” Brass said in a statement on Wednesday. “The cladding was an integral part of the design and made the extension part of the permanent look and feel of the building.”

“We certainly understand the importance and symbolic nature of the height of One World Trade Center. It’s an important building for many reasons,” Brass told WCBS 880 on Thursday.

“We are disappointed that a decision has been made to remove the sculptural enclosure at the top of 1 World Trade Center,” Childs told the New York Times.

“Eliminating this integral part of the building’s design and leaving an exposed antenna and equipment is unfortunate. We stand ready to work with the port on an alternate design that will still mark the One World Trade Center’s place in New York City’s skyline,” Childs said.

Port Authority spokesman Steve Coleman said he wasn’t worried about One World Trade Center losing the 1,776 number.

“One World Trade Center will be the tallest building in the Western Hemisphere,” he told the Times.

The Times also reported that removing the shell would save $20 million, but that Douglas Durst said the prospect of maintaining such a complicated structure so high in the sky was what really doomed it.

Last Monday, One World Trade Center reached 1,271-feet-tall, surpassing the 1,250-foot-tall Empire State Building as New York City’s tallest building.

Do you think the shell should be restored to the design or the antenna should be counted as part of the building’s height? Sound off in the comments section below.