My A1200 is from the Scottish plant. It says Made in UK or Manufactured in the UK... but it's definitely UK. Oh the keyboard layout was German.
I also think that the machines made in Braunschweig had "Werk Braunschweig" written on their boxes. I don't think that machines from other plants had something similar on their boxes.
My 1987 A500 v.1.2 has "Made in W. Germany" written on it, but there's no "braunschweig" note on the box. Perhaps this note was on later machines.
Some or all A1000s were made in Japan.