Sometimes the Internet weirds me out: like today, when in my Google News feed is the headline "A million-dollar flea market find" from the Philadelphia Inquirer. It's about the sale of what's now known as the Lear copy of the Dunlap Declaration of Independence broadside ... and the story is from May or June 1991 (sometime prior to the 4 June sale of the Declaration for $2.42 million, since the results of the sale are not mentioned). Norman Lear and others purchased the copy in 2000 for $8.14 million.
So no, there's been no new discovery of a Dunlap Declaration behind a $4 flea market frame. The story's just getting recycled, years later. And it's causing trouble already: Artinfo notes in a piece on the story that Sotheby's "plans to sell the document for the owner next June" - noooo, that happened ... eighteen years ago!