For nearly 18 months after unearthing the painting, Levine spent tens of thousands of dollars trying to authenticate the piece.
Here lies the quandary of unearthing or even bidding on ultra high end art without the correct provenance. For every one of these success stories, lies a thousand cases,, where the "lucky" guy ends up being tens of thousands of dollars poorer.
Picasso as an example...... It is widely known and held that Picasso was extremely prolific artist. However, only a very small percent of his art has that level of provenance needed for authentication. The value of a Picasso, versus one "Attributed to..." or "Manner of...." exponentially drops.
Here is an interesting article on the problematic nature of getting one authenticated. (warning: headache inducing)
http://www.artnews.com/2013/01/02/authenticating-picasso/