In 1992, a group of investors paid a modest sum for the Jelle de Boer art collection, which consisted of works the Dutch collector had judged to be lost creations of van Gogh, Matisse, and Renoir. The sale didn’t exactly set the art world ablaze, since de Boer’s stack of paintings had long since been judged to be fakes. But now, the current owners are asking experts to reexamine the collection, saying that they believe there may be a few authentic diamonds amidst the mass of imitations.