If Cuba and Venezuela can survive in America's hemisphere, then I'm sure right wing dictatorships could survive.
Eh, there is a thing to be said, however.
Cuba and Venezuela came from a ideological mindset, basically the idea to persue a goal that couldn't be persued by democratic means, to give a solution that wasn't possible without a dictatorship. This is the case also for the brazilian new state dictatorship (to overcome the Brazilian backwardness), for the Soviet Union (to persue socialism and communism), for the Chinese KMT or Ataturk turkey.
With the right wing dictatorships of the cold war, however, it was basically a bunch of opportunistic military personell who took over either by their own personel gain like Manuel Noriega, either because the US asked them like in the case of the 1964-85 military regime in Brazil, to fight communism, or because these junta wanted to purge a internal enemy, like the argentinian junta that took over to crack down on both peronists and communists. This kind of dictatorship is not built to last, there is little ideology apart from anti communism and cracking the head of the opposition, there is no dream of a long lasting regime to change the social order or fix structural problem, no concept of a greater good, so these dictatorships fall or democratize. The most brutal junta we know is the Argentinian one, and even they didn't wanted to turn Argentina into a stratocracy, had they won the falklands war they still would end giving up power to the civilians while their corrupt officers would retire with large pensions, with the only difference is that instead of traitors they might be remembered as the heroes that conquered the malvinas.