"This is our Platinum Night auction, our most prestigious auction of the year," said Jonathan Scheier, lead cataloger for Heritage Sports Collectibles in Dallas. He put together much of the auction's lineup and personally handled the Clemente bat.
"If you love history - and particularly sports history, as I do - it's great," he said. "The treasure-hunt aspect of it makes it particularly fun. You never know what's going to turn up."
The Clemente bat turned up in the attic of Andrew Baxter's parents, decades after he handed it to Clifford Baxter, a Pittsburgh police officer working crowd control at Forbes Field on Oct. 13, 1960.
Andrew Baxter's memory of his father's prize is a little hazy.
"I remember being in the kitchen and him coming in with his uniform and saying, 'Hey, guys, look what I have. I got this bat at the game, and the Pirates won. I got this bat from Clemente,' " said Baxter, a retired Pittsburgh public schools teacher who was 11 at the time.
Baxter and his two younger brothers, Denny and Clifford, did not grow up to be big baseball fans and forgot about the bat. Their father died in 1972, their mother in November 2010.
"After she passed away, we were going through the house and removing things, and my one brother said, 'Hey, whatever happened to the bat?' I said, 'I don't know. As far as I know, it's still up in the attic.' And we went up there and sure enough, there it was."
What was unusual about the bat was the name on it. And that is what makes it so valuable.
"Momen Clemente was his nickname as a child," Scheier said. "Apparently, when he was a child, he was often deep in thought, and when someone would call him, he would say, ' Momentito,' which meant, 'Hold on a second.' And that was how he got that nickname."
Clemente did not start having his bats stamped "Roberto Clemente" until the 1961 season.
"This is one of the final 'Momen Clemente' bats, which do carry a premium," Scheier said.
The autograph stamp is one of the ways Scheier confirmed the bat's authenticity.
"There are a few ways to do it," he said Thursday. "The story itself is part of that. But the physicality of the bat is the major part."
Hillerich & Bradsby Co., makers of the Louisville Slugger, keeps detailed records of the bats sent to ballplayers each season. Specifications such as the length, the weight, the type of wood, the taper of the handle, the type of knob, and the stamping on the barrel are meticulously detailed.
Scheier said game-used bats are hard to forge and second in value - among top-tier collectors - to game-worn jerseys.
"And Clemente memorabilia is huge," he said. "He's one of the most celebrated, most sought-after guys. His talent, his Hall of Fame credentials, and of course his martyrdom."
Clemente died in a plane crash Dec. 31, 1972, while flying aid to Nicaragua after a devastating earthquake.
In spite of the legacy, the bat did not mean much to the Baxters.
"There's no real attachment to it," Baxter said. "My brother wondered if it was worth anything. And I didn't even know people collected baseball bats. So I looked it up on the Internet and I came across one similar to this that sold for a tidy sum of money."
Just to be sure the auctioneers believed his story, Baxter sent Heritage an old black-and-white photograph taken as the famous game ended.
"It's a great photo shot from behind home plate of the chaos moments after [Bill] Mazeroski hit the home run," Scheier said, "and there's probably about 30 policemen running out onto the field. Some of them have billy clubs in their hands - I guess to start whacking all the fans who ran out there - and there's a red arrow pointing to his father, who is about at the shortstop position when the photo was snapped."
Once the bat was authenticated, Heritage listed it for Thursday's auction and entered into the company's website for Internet bidding. The online sale closed at $22,000 for the bat.