Brothers Keith and Brian Collins say they discovered Earp's personal photo album while picking through a Hesperia, Calif., antique shop, the Los Angeles Times reported Saturday.
"We split up to look for pictures in the store. We always do that," said Brian Collins, 40, of Victorville.
The tintype and carte de visite photographs show Earp as a child, a teenager and as a young adult, the brothers say. The album, which the brothers paid $50 in May, also contains photographs of his mother and two of Earp's three wives.
Wyatt Earp is best known for being the deputy marshal of Tombstone, Ariz., when the famous shootout at the O.K. Corral occurred.
The Collinses have invited experts to inspect the pictures and verify their authenticity.
"The problem is, nobody has seen pictures of Wyatt Earp as a kid. You can't compare them with anything," said Nicholas Cataldo, author of "The Earp Clan: The Southern California Years." "There are known pictures of Wyatt in his 20s and 30s and in some of them he doesn't look alike."
However, the brothers are certain the photos are authentic, saying they picked up photo analyzing skills from their late father, who was a sheriff's deputy.
"Our father taught us analyze photographs by measuring and comparing facial features -- the ears, nose and eyes," said Keith Collins.
The brothers say the album could bring in as much at $1 million if sold, but they would like to keep them and lease out the rights to their use.