A newly discovered photo of Billy the Kid, playing croquet with his gang after a wedding, will be exhibited for the first time at Witherell’s Old West Show in Grass Valley, Calif., Friday and Saturday, May 6 and 7, 2016.

Estimated at $5 million, San Francisco-based coin dealer Kagin’s is bringing the tintype to the Gold Rush era location and is handling the private sale.

Because the 1878 photo of the outlaw—bought in a Fresno thrift shop for $2—is only one of two known, the owner, Randy Guijarro, spent five years authenticating it.

Donald Kagin, Ph.D., President and CEO of Kagin’s, spent another year validating the original historic and scientific research.

While not everyone in the antiques field is as certain as Kagin about the rare find, Witherell’s is pleased that Kagin chose to debut the photo at the Old West Show.    

Two years ago, Kagin brought the Saddle Ridge gold hoard of 1,427 coins from 1847 to 1894—that are almost sold and nearing $10 million—to the show.

“We are delighted that Donald Kagin is joining us,” said Brian Witherell, chief operating officer of Witherell’s and a featured appraiser on “Antiques Roadshow.”

“We are as excited as everyone else to have a close look at this photo, given the way it came to light.”

“Discoveries” such as these are the dream of Old West aficionados, collectors and dealers.

After decades of being in a house, many descendants have no idea of the value of old items they inherit and unload them on thrift stores.

Nearly 2,000 people attend the Old West Show, including collectors who fly in for the two-day event.

Western Americana collector and energy billionaire William Koch—who bought the only other known photo of Billy the Kid for $2.3 million in 2011—has attended in the past.

Admission on Friday and Saturday is $10.00 for a one-day pass or $15 for both days.

Hours are Friday from 9 a.m. to 5 p.m. and Saturday 10 a.m. to 3 p.m.

Located in the historic California Gold Country, Grass Valley is a favored destination for second homes of San Francisco Bay Area and Central Valley residents who host parties during the weekend.

The 100-vendor show is held at the Nevada County Fairgrounds, 11228 McCourtney Road, Grass Valley, CA 95945.

Witherell’s also runs the online Western Design Auction concurrently and exhibits highlights of the 150-lot sale at the Old West Show.