This is indeed the main problem. If you have two screens of the same model, the OS is unable to see which is which. This also goes for many USB devices (such as webcams that randomly swap).
That way it would be up to the user to plug the same screen into the same port, which I think I could handle.
Plus I can see the serials are actually different, so just going by serials should work.
Or it should just tell you "hey buddy, you've got two screens with the same serial and that's why I don't know what to do"
Yes, this is the strange thing. It's not like it's guessing which monitor is which, it's always swapped.