Goliath Phallus: Is Michelangelo's David Holding Goliath's Severed Phallus?

Michelangelo's David
Galleria dell'accademia

Although the item in David's hand is ostensibly a sling, it is pretty obvious that Michelangelo intended to convey the idea of a power transfer between the slain and the victorious by depicting the successful biblical warrior-king David holding Goliath's severed phallus over his left shoulder.

I noticed this a few years ago, so I went to the Galleria dell'accademia in Florence, Italy today to take another look at the statue. The following black-and-white pictures are snapshots of image details from a book on David - Michelangelo's masterpiece - which book was on sale in the museum gift shop.