You made a fantastic deal with that saw. I wouldn't worry about changing vee belts. They will automatically reform to their designed length with time. A new matched set of belts is hard to find. I bought a "matched" set a few years ago but you could see flutter on one of the belts. It doesn't affect the running of the saw. It still cuts as it should. My saw has the Biesemeyer fence also. Great fence, although it is the original fence made back in the 80's. When Delta bought out Biesemeyer, their quality fell as I understand. Keeping the Unifence may be a good idea.