If you read American Desperado, the author verifies much of what Jon talks about through research and through confirmation from other individuals he interviews for the book. That period of time in NYC was insane and riddled with crime so yeah it's believable and the fact that this dude was in fact that rich which is a fact, he'd really have no reason to make this stuff up even so others verify his story and some are not named in the book as well like the model.