That seems like a good price to me.
That's about what it would cost you for a re-manufactured engine installed.
Is thee any problems with the vehicle that you know of?
Well, for what it's worth there were alot of timing chain failure on these engines as you know, but MOST happened at low miles. (under 80k kilometers) or started making noise prior to that. The ones that don't seem to have any issues up to that point don't really seem to have any significant issues from what i have seen. Your best bet is to listen for any rattles at start up, this would indicate a possible tensioner issue and you need to walk away. Otherwise the truck is probably fine, with any machine nothing is guaranteed obviously, but the odds or premature failures are lower at this point. Usually what I like to tell people with questions like this is, are the risks worth it for the savings? otherwise your going to worry yourself to death regardless of what I tell you.
In my opinion, with no chain noise at start up or high revs, then your fine and good to go.