led zeppPhoto: Warner Bros.

A San Francisco federal appeals court is considering whether to order a new trial in the copyright claim against Led Zeppelin's "Stairway To Heaven" by the estate of the late Randy Wolfe (aka Randy California), a singer/guitarist/songwriter for the band Spirit.

An 11-judge panel in the case is reportedly skeptical about the request, peppering the attorney for Wolfe's estate, Francis Malofiy, in a Monday hearing about his assertion that the audio version of the song, not just the sheet music, should be considered because the album version is much closer to "Stairway" than it appears on paper.

The claim in the case before the 9th Circuit U.S. Court of Appeals is that part of the legendary 1971 song "Stairway" -- specifically the famous opening riff -- was taken from an instrumental song by Spirit in 1968 called "Taurus."

READ: Is there an evil message when you play Led Zeppelin’s ‘Stairway to Heaven’ backwards?

And though Wolfe never sued Led Zeppelin when he was alive (he died in 1997), his estate filed a lawsuit against guitarist Jimmy Page and singer Robert Plant of Led Zeppelin in 2014, which it lost two years later.

A three-judge panel from the 9th Circuit ruled in June, however, that the trial judge didn't give clear instructions to the jury about what aspects of "Taurus" could be viewed as "original and protected."  And it was determined that a new trial should occur -- giving Wolfe's estate renewed legal life in the claim.

Reportedly, according to Malofiy, Wolfe talked to Jimmy Page numerous times during his lifetime about possibly receiving some compensation for what Spirit felt was a clear taking of its music without proper attribution.  But the lawyer for Wolfe's estate said Page always declined or suggested he would embroil Wolfe in years of expensive, legal maneuvering if Wolfe ever sued.

Led Zeppelin's trial win stood in contrast to other recent high-profile cases. Jurors decided in a 2015 trial that Robin Thicke's "Blurred Lines" copied Marvin Gaye's "Got to Give It Up," and a jury earlier this year found that Katy Perry's hit "Dark Horse" copied from a Christian rap song.