Oh yeah, that 91 had a lower clamping diameter of 56.6mm.
The 96 used a lower clamping diameter of 58.9mm.
The nice thing is the lower bearing was the same for many years, makes, and models:
FITS 92-05 KX125, 92-07 KX250, 93-96 KLX650R KLX650C, 95-06 KDX200, 97-05 KDX220, 91-94 KDX250, 94-96 KLX250, 06-07 09 10 KLX250S
So it stands to reason that you could use a lot of different lower clamps.
96-01 KX250 all had the same lower clamping diameter..
Mu "Guess" is you could use any one of them.
Give it some time and I'm sure others who have tried it will chime in..