I do not know the tractor, but do know that I would be curious if those 6000 hours were simple "key on" hours, or hours accumulated by a mechanically-driven hour meter that is based on engine RPM.
The mechanical hour meter registers one hour for each hour the engine is running at 540 PTO RPM on many, or maybe most, tractors using one. While the electric hour meter likely just shows key on time, and will continue to run, on at least some tractors, if the key is left on when the engine is not running.
For some reason this difference means something to me...I guess if I were looking at two tractors that had the same hours, and one had a mechanical hour meter, while the other had an electric hour meter, I would consider the one with the electric hour meter to have less actual use hours than the other.