The 6800 reference made me cringe a little too, but it might not be because of shoddy research or something. Could be the actor just screwed up and nobody noticed (or cared) because it was good enough, as far as takes go. The original writer might have thought it a cool idea to throw in a reference to the Amiga, but then there's rewrites, etc. And had someone brought it up, I imagine alienating a bunch of Amiga enthusiasts wasn't a huge concern..
The 'homemade OS' was about stupid though, especially when it looked like Workbench and added nothing to the plot. Even someone that knows nothing about the Amiga but knows about Windows, MacOS, and/or Linux is going think that was dumb.