As we all know
this engine for sale is certainly not an 'Abarth' engine as it is an 8 valve rather than a 16v. The gear box is not an 'Abarth' box either - it is merely the shifter that is 'Abarth' - the rest is basically the same as in the 132.
In my opinion (and experience) I'd say that the engine looks like a 131 B2.000 from a 131 Sport/Racing (therefore a 1,995cc Twin Cam) and that the gearbox also came from a 131 Sport - but whether they came from the same car is another matter.
The best thing to do though (whilst it won't definitely tell the story, but could lessen the doubt) is ask the seller to remove the dizzy cap and send you a pic of the internals. If it contains points and condenser then it's likely to be a smaller engine, as all 2,000TC has electronic (contactor-less) ignitions.
Ian, do you know if the engine is in good internal condition? It's not worth much if it's seized - same for the gearbox, even an 'Abarth' one