Carbie engine showing the 2 pickups under the flywheel, albeit not too clearly;
Later injected engine, all be it a 4v so maybe not the same as 900i.e.? showing the 'missing' tooth (actually 2 teeth) setup that a single sensor reads from, there is no pickup on the flywheel as the sensor fits through the outer crankcase and simply 'looks' at the timing gear.
Obviously you can remove the pickup from the 'i.e' type (carbie cover doesn't have the hole in the case) and there should be the mounting holes for the 2 pickup bracket from flywheel assembly. What I don't know is whether the carbie flywheel is interchangeable with i.e. alternator/flywheel as the 3-phase alternator is (in 4v engines anyway) a different setup and the flywheel to crankshaft fitting is different.
There maybe ways round this but it might not be plug and play?