Back in August 2013, Swann's Photographs specialist Daile Kaplan appeared on an episode of the Roadshow to discuss Lange's most famous image during a visit to the Nelson-Atkins Museum of Art in Kansas City. See the video here.
At the time Daile commented that, "the grit and determination that she conveys in this picture was authentic," and she went on the explain that modern prints of the image can sell for anywhere from $40,000 to $200,000 at public auction.
Indeed, a 2005 sale at Swann saw Migrant Mother bring $33,350. And, a later printing, by Jon Goodman, in conjunction with Aperture, in up for auction at Swann on Thursday.