The OS carb bolts directly to the rear cover..the MVVS uses two bolts to bolt the carb to the engine from a ring around the end of the carb....the mounting methods are completely different. I can't say if the bolt patterns are the same, but the OS has a smooth machined surface that mates to the rear cover, the MVVS is more of a conventional carb but has the long screws along either side.
At any rate, I would imagine the carb for the OS would be as hard to come by and expensive as the VRDX is...

MVVS has a large bore version of the 3226 carb..