Welcome to the forums...
NYCruiser is correct, with so little info its hard to give an opinion if it'll be a good truck... here's what I can tell you...
1) Mileage is high for the years... I consider a low mileage lease rate as an average to work from, which in Canada is 20,000kms.
2) Although it has the venerable Cummins engine, many operators have had issues with the 6.7/dpf system and many where possible have deleted the emissions equipment. This may be good or bad, depending on your view and the laws that you are bound by. Know that if your truck has been deleted it has had a programmer on it, which can be bad if the previous owner bagged on the truck or thought it'd be 'manly' to blow smoke for his friends.. on the other hand, many ops run their trucks without damaging them as they respect the fact that 'just be cause it can, doesn't mean I should' mentality (read: rail pressure, etc)
3) Minor note... its Cummins, no g..
So ya, its very dificult to say but that should give you a little to work with... by all means if you have link to an ad, post it up, get us the specs and we'll all give our opinions... they are just that however, opinions and many of us are keen operators like myself, not mechanics so take the postings with however much salt you need..
Welcome!