Sixteen-year-old Don Lutes Jr. found the lucky penny in his school cafeteria in March 1947, and held on to it for more than seven decades before dying in September without confirmation of its actual value.
The cent is one of the most famous error coins in US history, pressed on copper and not zinc-plated steel.
In 1942, pennies were supposed to be struck from steel, in order to conserve copper for shell casings, telephone wire, and other "wartime necessities". One penny, in particular, is now dubbed the "most famous error coin" by Heritage Auctions, who is auctioning the penny.
A rare penny that was expected to fetch $1.7 million at auction Thursday went for a mere $204,000.
A similar penny sold for $1.7 million in 2010.
It was even reported, falsely, that Henry Ford would give a new auto to anyone who provided one of the rare coins to him.
Karpenski said he met Lutes in 1970 when he joined the Berkshire Coin Club.More news: Oscars Will Go On Without Host for First Time in 30 Years
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Before the switch to steel just a few pennies were mistakenly minted in copper.
Only a handful of such coins have ever been discovered, according to Heritage Auctions. Zinc-coated steel plates were "considerably harder" than those used in earlier designs, so penny pressers had to strike the blank steel coin much harder. After Lutes's health started to decline, he moved to a nursing home.
Lutes even tried to get the authenticity of his penny verified by the Treasury Department.
In 1958, a copper penny from 1943 sold at auction for $40,000 - the equivalent of $350,000 today.
A few bronze blanks were caught in the trap doors of the mobile tote bins that were used to feed the coin presses, and they were fed into the coin press along with the steel wartime blanks, auction officials said.
"Despite the mounting number of reported finds, the Mint steadfastly denied any copper specimens had been struck in 1943", Heritage Auctions added, referring to the US Mint, which produces coinage for the US.