Sounds like a lot of Islamist wank to me to try and surpass the Jewish/Biblical account of King Solomon, and is probably why the countries that he reportedly ruled over are such economic powerhouses today.
Yeah except in that time Mali was renowned for their massive supply of gold (and salt) and the Mali Empire was one of the richest empires in history under Mansa Musa. On top of that, most modern historians believe Arab scholars and historians a lot more than they do Christian ones (I wonder why) and I'm fairly certain there's a number of westerners at the time who noted this actually happened on their travels in Egypt (Venetian merchants in particular). So yeah I (and just about everyone else who knows about this) am fairly certain it's not "Islamist wank".
Also if we're going to discuss empires who are still economic powerhouses should we go into detail about Greece, Italy , Spain, Portugal or Mongolia?