For what it's worth. Way back in the 1880's there was another round known as the .45 Schofield. This fit the S&W Schofield revolver that the Army procured in limited numbers. It was shorter than the .45 Colt and had a bigger rim so as to work with the S&W extractor. The Schofield round would work in most Colt revolvers but you could not use the Colt round in a S&W. Some Colts due to manufactining tollerances could only Chamber 3 leaving an empty chamber between,due to the bigger rim, a few could not chamber them at all
Well, the obvious happened. Troops with Smith's got Colt ammo, and were left without a shooter. The Army preferred to issue Colts and they became the standard but they did make a shorter version of the 45 Colt round, with the same rim as the Colt that would shoot in both guns, though it may not have extracted well from the topbreak Schofield revolver. This was called 45 Revolver Ball (IIRC). So in the old days there was a short and long version of the 45 Colt.
Technically .45 Colt is the correct name. BUT, you can buy guns and ammo that are marked LONG COLT or LC so it is reasonable to refer to it as such. The only one who would argue about calling it Long Colt are insecure rectums who try to make up for their inadequacies by attempting to chastise others.