Were the Birchers right about the UN?

In their discussion of the alt-right, Hugh Hewitt and Jonah Goldberg mentioned William F. Buckley driving the John Birchers out of the conservative movement. Here is what I remember about the Birchers. When I was living in Texas, the Birchers put up billboards urging Americans to get out of the United Nations. I don't know what else they advocated, but the UN issue seemed to be their biggest issue. I think they were right on that issue. What do you think?