And that section of the Wiki article has a note at the top saying:
"This section relies largely or entirely on a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. (July 2014)"
And that specific claim isn't sourced at all.
If you google search Union Pacific Flags and Flares, you get 1: That wiki link, 2: This thread: 3: a link to Pentrex: Flags, flares and Wings. which is a video specifically about the SD70M-T1 with the flared radiators. I'm not saying it isn't a thing people say, but I've never heard it referred that way until this thread.