Hello! I am brand new to the biking world and I am trying to find a good (decent?) used bike on craigslist

I am looking into a use Trek 930 Mountain Bike right now.
He reports that he recently "replaced the drive train, brakes, brake levers, wheel set, and tires" and asking $180.
The bike frame is 17.5" which is perfect for my height (5'6").

Here are direct links to pictures to determine if these replaced parts are good quality AKA worth the price:
http://i57.tinypic.com/2cnumx0.jpg
http://i59.tinypic.com/25pr23n.jpg
http://i58.tinypic.com/qnjuqr.jpg
http://i61.tinypic.com/eaijw3.jpg


Thank you for any feedback