Is this a good deal ? Work truck/tow rig

Those old 12 valve 5.9 Cummins are great motors even tho you can hear them comming from a mile away..They are a little harder to increase horsepower on as the updates are mechanical.If it has been serviced properly that kind of milage is barley broke in kind of miles.The newer ones you can just chip them and help em a bunch.Like Badsport stated I would offer him $3500 and see what he says.Always ask for proof of updates or improvement.