Of course yes, GUIs go all the way back to Sketchpad in 1963. The PARC work was more about putting files on a server than putting the application logic on a server. X11 put all of the application on a server (or as X11 calls it, a client…). Based on my bookshelf, the “client-server” paradigm of putting the UI part and a substantial portion of the related logic on the client, but with most of the business logic on the server, reached mainstream adoption in the 90s.