No she was not.She was against Reagan's plan to end the Urengoi 6 pipeline and end Soviet access to Western Technology.When BLACK FRIDAY hit she was with the French and West Germans not us.
Maybe it was an overstatement to give Thatcher equal credit, but she was typically Reagan's only supporter in NATO, and her rejection of Socialism when the rest of Europe was embracing it set a more visible example to Eastern Europeans through remarkable economic growth.
Generally, the three of them are all given credit, whether you like it or not. But that wasn't my point anyway. My point was that she was a much better leader than a lot of the presidents that this country has produced.