In the context of popular things like HTTP and SMTP, yes, it was mostly Unix/BSD/NeXT[0][1]. Obviously the entire history of the Internet is a different story.
[0] https://en.wikipedia.org/wiki/World_Wide_Web#/media/File:NeX...
[1] https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol#...
Was it? By my reading there was way more weird stuff than there is today but I certainly wasn't alive back then.