The .38-caliber Colt Cobra, which has been in private hands since 1967, will be auctioned at the Palms casino in Las Vegas, the Las Vegas Sun reported Tuesday.
The newspaper reported that artifacts relating to the 1963 assassination of U.S. President John F. Kennedy in Dallas and the subsequent slaying of Oswald wound up in private hands, with the exception of the rifle Oswald used to shoot the president.
The rife ended up in the National Archives in College Park, Md., along with other evidence from the Kennedy assassination.
Gary Mack, curator of the Sixth Floor Museum at Dealey Plaza in Dallas, told the newspaper he hopes the gun will return to Texas.
"It would be really nice if someone would buy it and donate it to us for the tax write-off," he said.