That is how Howard Zinn writes and wrote ‘A People’s History of the United States’, he didn’t just make everything up, he mostly just cherry picked what he wanted to include, didn’t include what would have hurt his preconceived view and he saw everything through his own biased conclusion that he wanted to reach.
When a source is as bad as The Nation, it is useless. I used to try and wring some value out of The Nation as you are now, and I finally gave up on being able to find any usefulness with the “oldest weekly magazine in the United States and the farthest Left of all popular American magazines”.
My source for this story was Viet Nam Veterans Against John Kerry. I read about it in 2004. I also seem to remember reading about it earlier on Newsmax.com, back when I read Newsmax. I think they used a former North Vietnamese Colonel as a source for some of the information.