In those years the model number corresponded to the gross horsepower - so it's probably 22.5hp - which would mean about 19hp available at the pto.
They are durable units - the mechanicals hold up great, even with hard use. They rarely develop leaks. Unlike some other brands, the basic hydraulic and fuel tubing is properly manufactured, so doesn't rattle apart. Kubota's build quality was very high in those years - they were trying to penetrate the US market and their quality is what pushed the door open. The paint does not resist sunlight too well, but they put it on over properly cleaned surfaces so rust from behind is not an issue. The upholstery and tires may look bad but the engine and transmission are probably near perfect with so few hours.
I'm pretty sure these have a 2-stage clutch. There is an easy check for main clutch wear. With the tractor off, engage the pto lever and have a helper push the clutch pedal all the way down. Then try to turn the rear pto shaft by hand. If you can, fine. But if you can't, the pto clutch isn't releasing and the main clutch may need replacing. (the next level of testing would be with an attachment hooked to the pto - see if the pto clutch can be disengaged).
Some of the small external levers on these models have cracked welds that eventually break. If you see evidence of weld repairs on a lever it's probably just normal.
Hope this helps. Take care, Dick B