I think that if Marcone had anything from Siro's Hord, he wouldn't be magically winning at life and somehow becoming an equal peer with Mab and Hades overnight.
Remember there was a WoJ on Siro and how nobody wants to touch his stash because it has a Fuck-Mothering Dragons death-curse attached to it.
To play Devil's Advocate, how did it work out for Bony Tony? It could very well be that the death curse affects whoever takes it from his stash, and that contact with the goods after it's stolen wouldn't transfer the curse; a loaded musket, once fired, requires reloading. Though it could just as easily be like uranium.
That aside, I've never thought of it coming from a dragon's hoard in the first place. It's a fun idea, and could very well lead up to the inevitable Dragon Book Jim mentioned in a handful of Words of Jim (Word of Jims?) but it seems a bit unlikely that Tony would have known about it and accessed it. But, putting on my paranoia hat, this could have been the work of the Circle trying to stir up trouble and tossing some problems Marcone's way to limit his influence in Chicago.