Gaps have held the attention of Washington, D.C., for decades.

During the Cold War, there was the missile gap, based on the false premise that the Soviet Union was outpacing the United States in amassing nuclear weapons. Economists have long argued about the wage gap, and pollsters have spent untold hours dissecting the gender gap after last year’s election.

The newest gap that has appeared in the nation’s capital, however, has to do with gold.

The gilt gap separates President Trump’s Oval Office, which he has adorned with gold details and tchotchkes since taking office in January, and a newly redesigned life-size replica of it that lies just across the street at the White House Historical Association’s People’s House exhibit.

The association has been around since 1961, but the immersive Oval Office tour opened just last fall, with the goal of being an exact replica of the most famous room in the country. Until the Trump transformation was unveiled late last month, visitors who came had seen a room looking almost identical to the one occupied by former President Joseph R. Biden Jr.

But the gilt gap renders the newer replica far from exact.

“We are replicating President Trump’s complete tenure within the Oval Office,” said Luke Boorady, the exhibit’s managing director, “starting with his first-term décor.”

Ann Compton, the chair of the association’s advisory council, said the decision to go back in time was purely logistical.

“You can’t go and buy anything that’s in there right now,” Ms. Compton said. “You have to have it made.”

“They just couldn’t make it all in time,” she added.

Mr. Trump, a real estate developer with strong — and heavily gilded — views about interior design, has been fiddling more with the White House complex in his second term. He paved over the Rose Garden and made it into a Mar-a-Lago-like patio after lamenting that women’s heels would “go right through the grass.” In June, he oversaw the construction of two 88-foot flag poles that straddle the White House. And last week, he announced his latest project: a 90,000-square-foot ballroom estimated to cost $200 million.

But the Oval Office replica is a throwback to his first term. It is strikingly similar to how Mr. Trump had the room set up back then, with many of the objects 3-D printed to mimic the real thing. The books on each shelf are the same and sit in the same position. The portraits, though printed instead of painted, appear identical. So does the Reagan-era beige rug and Frederic Remington’s “Bronco Buster” statuette (which Mr. Biden removed).

“We used a lot of the same vendors that do work at the White House,” Mr. Boorady said, citing the people who installed the floors and upholstered the furniture. (Mr. Trump’s sofas were first used by President George W. Bush.) “In fact, when they came, they noted, ‘Hey, you’re off a half-inch here, a quarter-inch off here.’”

Of course, not everything can be exactly the same. The Resolute Desk has only one phone instead of two, because visitors kept tangling the lines. Unlike the real Oval Office, there is no bust of Abraham Lincoln, as it would block the exhibit’s accessible entrance.

On Saturday, parents stood in line as tired children sprawled out on couches meant to mimic those where top officials sit in the real Oval Office. Many visitors were thrilled at the opportunity to sit behind the Resolute Desk and make an imaginary phone call to a world leader. One woman enthusiastically endorsed the feature on the presidential desk known as the Diet Coke button, musing about one day getting her own that would instead summon gin and tonics.

And some said they wished Mr. Trump had never veered from the first-term version.

“I think this one’s nice,” said Hunter McElroy, a 25-year-old property tax assessor from Morgantown, W.Va. “I think this is a little more classier, with a little bit less gold.”

Hoang Vo, a software engineer visiting from Dallas with his family, had toured the White House earlier in the day but had not gotten a chance to visit the real Oval Office, so he was mesmerized by the chance to experience something similar in person.

“It’s cool and very unique,” Mr. Vo, 55, said of the replica.

Others, however, were not convinced.

“I don’t like it,” said Maria de los Angeles Sapriza, 63, who was visiting from Uruguay. “I think it’s a little bit fake.” Her eyes widened when she learned about the additional gilt brought in by the president, reportedly with the help of his Mar-a-Lago “gold guy.”

The gilt gap will vanish next year, when the association plans to transform the replica to mirror the current décor of the Oval Office.

Staff and visitors alike said they were excited to see the exhibit match the Oval Office in its current form. But that may be a daunting task given Mr. Trump’s addition of the many golden objects, onlays and other detailing. The White House, Ms. Compton said, was helping with the transformation, but “it keeps changing,” she said. “They keep adding things.”

“We have to go out and find our own people to make the things not on the shelf,” she added.

But Mr. Boorady said gilding up the replica would be no problem.

“I don’t think the lift is going to be that different,” he said. “It’s just more objects.”

In due time, he said, someone would be on a ladder adding gold ornaments to the ceiling, and the gold trophies adorning the mantle would be no different from the ones across the street at the White House.

“We want visitors to be able to feel the White House, experience it, understand its long history and the important things that have happened,” Mr. Boorady said.

And as for the behemoth of a ballroom Mr. Trump is promising to build, the association has not yet begun contemplating a replica.

“We haven’t really thought about that,” Mr. Boorady said.