2012 ISX t800

[SB Ag]

Looking at purchasing a 2012 t800 with a 2250 isx set at 500.
400k kms (250k miles) on the truck, has a brand new complete drop in engine 3000 kms ago. 3 yr warranty on engine. 1 owner truck came from a good home, emission equip has been taken care of ( still legal to delete here) just wondering what are some things I should be looking for, and what kind of life should I expect from this engine? Mostly hauling b train hopper trailers or 4 axle end dump. TIA