I doubt it had anything to do with him being their union president 25 years earlier.
I accepted the nomination and position of safety steward in my union not because I loved the union but because I could do some actual good by protecting the company from potential lawsuits and my fellow employee's safety.
You may be right, but President Reagan had an ability to work with everyone, even those who completely disagreed with him. I found that out from personal experience.
During my senior year in HS, I wrote to then-Governor Reagan expressing my outrage of the diversion of water from Northern to Southern California. That water should have flowed into SF Bay. Anyway, it was full of the vitriol and lack of understanding one would expect from a 17YO.
A few weeks later I received a personal reply. Unfortunately, I lost that letter during my various moves after high school. I'll never forget the opening lines of his response, where he thanked me for my letter, saying "thank you for your letter. I enjoy hearing from young people like yourself, because you bring such passion to the issues of the day."
The response was vintage Reagan, and there's no way a staffer could have ever penned such a letter.