AFAIK, main exporter of AK was China. Well, isn't the idea of providing cheap reliable and effective weapon to everybody who wants in perfect correspondence with "American Dream"? God made men, but AK-47 made them equal.
Maybe but USA undoubtedly always had much more influence on Cuba and its fate than USSR anyway. BTW Cuba is not so bad place now. Many people say that it is much better than it was before Castro's revolution.I think Cuba just might be different if not for the USSR.