They didn't in 1960, claiming that Kennedy cheated. in 64, they warned against big cities with fraudulent voting. They also claimed that Bill Clinton didn't win fairly (plurality, not majority) They were going to challenge Gore's victory in 1992, but then he won and though they were saying that

if Gore won the EC but Bush won the popular vote, Congress should step in and make Bush the winner. Of course, they flipped the script when Bush was able to get the EC handed to him. So claiming fraud, etc. is not new. It's always directed toward big cities because you know who lives in big cities.