You mean the "Koopa" sign in the main map?
I completely forgot about that one, I just saw English letters and assumed it was okay lol
I forgot to localize that one it seems.
Super Mario World did change the "Koopa" in the Japanese release in Bowser's castle to read "Bowser" instead, so perhaps doing the same here would be adequate.
However, it's been years since I last touched this translation, so I am not even sure if anything from the map was touched upon in that regard.
I'll try to see what can be done, but I can't guarantee anything.