Sourced a 5.3L Is this a good idea?

[Sturvin]

I'm thinking of swapping a 5.3L into my truck. Having never swapped over a computer controlled engine, I have a few questions.

Found this on craigslist. Since I have a limitied idea what the going rate for a 5.3L setup is and I don't know what is all involved (yet) my question is:

Is it a good idea to grab an engine out of a car that has already been swapped?

On the plus side, it includes the computers and it is easy enough to test to cooling system.

On the bad side, I'm not sure if they cut out something I might need?