For sake of ease, Epiphone used the same color suffix for the Riviera II and the Supernova ML. The Riviera II is the same guitar as the Supernova without the signature touches. A few years after the Supernova was released, Epiphone started producing the Riviera II for the Japan market with the same colors ar the Supernova, save the Union Jack finish. ML is a typical custom color that Epiphone uses on quite a few guitars.
I'm just trying to shed some light on Epiphone's color suffix designations.
Looking forward to seeing the Guitar in the flesh. I'm actually picking one a 1998 model of these up along with a 2007 Sheraton in a trade for a 2005 American Series Strat tomorrow night. It is Manchester City blue which is Noel's favourite football Team.