The rumors swirled all summer: a hip-hop El Dorado, a treasure trove of lost recordings by old-school greats like Big Daddy Kane and Biz Markie, had been discovered in an abandoned storage locker in New Jersey.

Then, in August, an album called "Top Shelf 8/8/88" was issued in Japan. Supposedly a collection of never-before-released recordings from 1988, it came with a back story that was even more elaborate than the rumors. And as the music spread on the Internet, skeptics set blogs ablaze: was it a hoax?

The album's liner notes told this story: An unidentified New York hip-hop aficionado scavenging through a storage locker near Hoboken, N.J., discovered a box of studio reels. The only clue to their contents was a name scribbled on a label: "Fab Five Freddy," the hip-hop impresario who was host of "Yo! MTV Raps" in the 1980s.

According to the story, the reels turned out to be recordings from hip-hop's fabled golden era, taped at a studio called Top Shelf in a basement in the East Village of Manhattan. The reels were supposedly lost during the Tompkins Square Park riots of 1988, and the studio later shut down.

Built on loops of classic soul songs and with rap that is at least four times faster than what is usually heard on the radio today, "Top Shelf" is peppered with references to Michael Dukakis, the Pontiac Fiero and the first "Die Hard" film. But why, as fans wrote online, do some of the supposedly teenage rappers sound hoarse and winded? And how come nobody has stepped forward and claimed to be one of the "anonymous Top Shelf producers" credited with the album's excellent productions?

"I wasn't expecting all this Internet action to take place," said Benjy Grinberg, the owner of Rostrum Records, the Pittsburgh label that will release "Top Shelf" this fall. He said the story was true, adding: "I love reading these hip-hop heads go back and forth and pick apart the lyrics. To be honest, I like the doubts."

The "Top Shelf" dispute is the third major controversy over rediscovered hip-hop recordings this year. Paul Winley Records in Harlem issued two discs said to feature routines from Afrika Bambaataa's late-1970s performances. They are billed as sequels to Mr. Bambaataa's famous "Death Mix" album, but as many listeners have pointed out, the style of performance and the quality of selections do not seem to match those of their predecessor.

Also this year, a British label called Golden Reaal issued "Live Convention 77-79," supposedly a prequel to two rare early-1980s rap compilations. While some dispute the recording's authenticity, it has been nearly impossible to debunk the elaborate back story. Golden Reaal has said that the rediscovered mixes were lost to a robbery in the early 1980s but recovered in 2004 from - sound familiar? - an abandoned storage facility in New Jersey.

The interest in these obscure recordings, which aren't going to make anybody rich, surpasses mere nostalgia. They suggest a yearning for the craft and ethics of a bygone era, before hip-hop became big business.

A Wikipedia entry for Top Shelf Recording Studio has been listed since May 2005. But the entry does not list a street address for Top Shelf, and Fab Five Freddy, the executive producer of the album, won't reveal it. In an interview conducted via e-mail messages, he said that it was in Alphabet City near Tompkins Square Park and belonged to an old friend who was an audio engineer and a marijuana dealer.

"Because of the nature of his business, even though it was a long time ago, I don't want to put it on blast like that," Fab Five Freddy wrote.

But several hip-hop producers who were active in 1988 said they had never heard of Top Shelf. The producer Howie Tee has worked with Chubb Rock and Special Ed, two artists on "Top Shelf," but he does not recall their mentioning the studio. Dante Ross, a rap producer who grew up on the Lower East Side, also said he did not recall the name.

Given that the story is set during a period better known for great music than for reliable bookkeeping, and that many of the era's stars say they barely remember what they did 19 years ago, the truth is hard to ferret out. Grandmaster Caz appears with Melle Mel on a song called "The Battle is On," and although Top Shelf is mentioned in the lyrics, Grandmaster Caz has no recollection of when or where it was recorded. The year 1988 "was kind of a blur for me," he said.

Brian Coleman, author of "Check the Technique," an oral history of hip-hop, said: "People who really know the deal from back then could poke holes in this fairly easily. But that would be a misguided thing to do. People should be celebrating the fact that someone did this."

Mr. Ross agreed. "If it's a hoax, it's kind of funny," he said. "I think it's funny when people create something mythical, if it's done tongue in cheek. It sounds to me like a hustle."

Dres, a member of the group Black Sheep, appreciates the exposure he has received from his track on "Top Shelf," "I'm the One." When asked how he became involved with the project, he said that Mr. Grinberg gave him a track and asked him to participate.

"I put a lot of energy into it, and reminiscing about back in the day," he said. So it is a hoax? Yes, he said. "At the end of the day, anybody really listening to it - you know, it ain't that hard to tell," he said.

Afrika Baby Bam of the Jungle Brothers, who contributed the track "Back in the Jungle," which he said was recorded in 2003, dismissed concerns about the authenticity of the project. "We still remember the culture and tradition," he said. "How much more do you need, outside of the actual date, to make a record as authentic as you would have made on Aug. 8, 1988?"

When asked to comment on these debunkings, Mr. Grinberg speculated that some of the artists might have gotten confused during the "re-production of the songs," which he said involved cleaning up the old tracks. He added that he was "not out to convince anyone of anything," and suggested that the album's ultimate aim was to correct the misdeeds done to these oft-forgotten artists who "didn't get the same amount of money or accolades that rappers today get."

Fab Five Freddy was vague. "The real story is the music," he wrote.

When the album is released in the United States, Mr. Grinberg may have some bigger headaches than skeptical bloggers. Special Ed said that he had no idea how his song "This Mic" found its way onto "Top Shelf," and that the track was a sped-up version of a song that he recorded in the late 1990s.

"I never heard of Top Shelf Studios," he said. "This is news to me."