That is the reason for the existence of the two parties, yes. Of course, that does mean there are other differences: FG traditonally tend to do better in middle-class areas like South Dublin; while FF is traditionally more nationalist and the party of culchies and chaps with the arse out of their trousers who live in bogs and craggy outcrops. However, there is little or no ideological difference between them in terms of economic or social policy.