Behind the Mac, as in, behind the Mac as it actually shipped, no. His ideas had little to do with it - it was almost entirely stuff designed by others when he was out of the project.
This concept of a story has been on HN so many times. It always starts with this technically correct but actually misleading headline fragment. Misleading clickbait works, even here. Every time.
Behind the Macintosh project, yes.
Behind the Mac, as in, behind the Mac as it actually shipped, no. His ideas had little to do with it - it was almost entirely stuff designed by others when he was out of the project.