how to tell if your 273 car was originally 2 or 4 bbl?

I have found my new to me 66 dart has the original 273, and the vin code shows a 273, but no way to know if it was originally a 4bbl car. The car has the correct 4bbl intake, but has a weber 500 cfm 4bbl and does not have the finned valve covers. So that makes me think it was an original 2bbl car but I do not know anything more. It has had the engine rebuilt, balanced and blueprinted with a nice cam to my knowledge though. It sure shreds like it has at least 235 hp.