Both M104 cams turn clockwise from the front with chain over top of both. The M120 chain loops under the intake cam ( CCW rotation ) on it's way to the other bank.

The real question would be are the exhaust cams different lift / duration? On a M104 It is possible with slight mods to install the exhaust cam into the intake side for a bit more lift. If the M120 exhaust cam was bigger than the M104, something could be gained.