Well, without me knowing, try this theory
These old distributors had 2 fingered rotors, each finger igniting 4 cylinders. On the one distributor version with single plug, one finger of the rotor ignited one bank of the engine while the other finger ignited the other bank. On the twin spark version with two distributors the one side distributor took care of the 8 plugs on one side and the distributor on the other side took care of the 8 plugs on the other side.
So the Stradale with one distributor/2 coils could have the old engine with single plugs, while the other with 4 coils could have two distributors and the newer twin spark engine.
Referring to the Fusi book on all Alfa cars:
Only the 33/3 had the Dinoplex, this is a later Tipo 33 Version with 3L 32Valve and single plug arrangement.
The 33/2 Sport prototype and 33/2 Stradale twin spark is specified like this:
With battery, 2 rotor fingers(2 spinterogeni), 4 coils and 2 plugs(10mm) pr
Hope this helps somewhat, if I am wrong, well sorry