Different 200 engine casings

How many different casings for a 200cc Vespa engine exist?

3 I think, P range, Rally & Cosa, as far as I know P range & Rally are fully interchangeable whereas Cosa’s inturnals are interchangable with P range but it’s casting are externally different & apparently Cosa engines won’t fit into anything else.

There are two types of Rally 200 casings , Femsa and Ducati types and both of theses at some time or other have been offered at various places in the world both with and without Oil Mix.
Also PX casings are split into at least three types , oil mix , non oil mix and electricstart. So effectively there are at least 6 different types.