It's one of these right?
http://www.specialized.com/us/en/bc/SBC ... sid=07Epic
Check condition of pivots by removing shock and see how gritty the bearings feel. Also check for lateral play.
Important to check that the carbon round the bearings in the main frame is not damaged. Look for small cracks/deformations.
Re. shock - only way to test it is to ride it. Does it lock out when it's suppose to and does it move when it's supposed to. Brain valves are "sensitive" and need regular services. Find out when seller last had it serviced.