The iconic Gibson Les Paul Black Beauty sold for $335,000 at Guernsey's New York on February 19.
The lot dates to 1954 and was the first to be built to guitarist Les Paul's exacting specifications. Despite this, for many experts and collectors it was overhyped prior to the sale.
Some parties were predicting a $2m sale, which would have made it the world's most valuable guitar.
It was consigned by Tom Doyle, Les Paul's assistant.
Vic DaPra, a Pennsylvania based dealer explained to the Washington Post: "I'm not disclaiming the guitar's importance.
"Les probably played it on his show but the guitar's been bastardized so much over the years. It is definitely not the Holy Grail and it is definitely not the guitar all other Les Pauls are based on."
His sentiments were echoed by Joe Bonamassa, a well-known blues guitarist, who told the publication: "What it is is a carved up old Les Paul Custom that Les modified and gave to Tom.
"I think Tom has the best of intentions with the guitar but Tom, because of his closeness to Les, may have an unrealistic value in his mind."
Indianapolis Colts boss Jim Irsay, owner of a prodigious guitar collection, was the winning bidder.
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