The thing is that that first windowed interface has such striking resemblance stylistically to the Smalltalk interface (see Smalltalk 76, black titlebars, minimalistic windows, etc) I'd have a hard time believing it wasn't influenced by the visit.

Even more so, look at this Smalltalk 74 interface here: https://computerhistory.org/wp-content/uploads/2020/12/Small...

I'm still not clear on what the Apple team saw at PARC that day, but it seems like it made a huge impression at least to start.