With a Jewlers loop, I can read "Dunlop" on the rear tire of the 465X on the Suzuki Brochure I have.
The brochure only lists the sizes, not brands, in the specs.
3.00-21-4PR, full knobby
5.10-18-4PR, full knobby. For the 250 (and 465)X's
The 125X was speced with a 4.10. Rear.
I love old brochures- the 125 had a dry weight of 88kg - read it and weep 250F owners. (Myself included)