is this true? 

3.   Most stock shocks are not re-buildable. IE: The Oil and Nitrogen cannot be replaced.
      Once the oil and nitrogen in the shock is broken down (worn out), the shock is 
      Rendered useless. It will not dampen properly and you will only be utilizing the
      Spring which is already way too soft. The average stock shock is Junk after about 80
      Hours of average use