Brother, I've looked at a bunch of GZ 125 photos and I got to tell you that they
look identical.
That being said, I can't find the tank or fender part numbers for the 125 to compare to the 250.
So..... your guess is as good as mine. If you can get the Suzi part numbers you can compare them here.
Ron Ayers Microfiche
Let us know what you find out. Good luck.