Over the years of production of the Sport Coupe it came with a 1438 with a single carb, 1608 with a single carb for the US and twin carb in the EU, 1592 single carb and ended with the 1756 single carb. All were twin cam motors. Early cars came with a four speed manual with a five speed as an option and then standard with the 1608. As production stopped in 1975 at Fiat they never fitted the 1995cc engine to the car in any market. The 131 two door took its place in 1976, became the Brava and then the Super Brava with the onset of FI and the 1995cc engine. Production of the 124 Sport Coupe continued at SEAT in Spain
There was never an Abarth Sport Coupe. There were some Jerarrri Sport Coupes out of California which had plenty of aftermarket parts appended to them, quite rare.
So the only twin IDF examples would have been on the 1608s in 1970 and 1971 and only in the rest of the world, not in the USA. I am not aware of the 1592 being available in the EU with twin carbs but it could have been. The change to 1592 was due to tax reasons for it to be under 1600cc, this engine was also the first of the 132 engines which is the engine series for the 1.8 and 2.0 engines.
You can put twin IDFs on any of twin cam engines, they weren’t just the realm of Abarth.